Funding for this work was provided&#160;in part&#160;by a research grant awarded to M. F. Salvatore from the National Institute on Aging (AG040261). The authors would also like to acknowledge Victoria Fields for her assistance with the behavioral experiments associated with the work presented&#160;and Mackenzie Orchard for his assistance with construction of the backstop for the treadmill.

All of the following procedures are conducted in accordance with the Institutional Animal Care and Use Committee at LSU Health Sciences Center-Shreveport, and comply with the National Institute of Health guidelines.
1. Pre-exercise Procedures
Note: A timeline of all of the relevant procedures in this forced exercise regimen is diagrammed in Figure 1.
<img alt="Figure 1" fo:content-width="5in" src="/files/ftp_upload/51827/51827fig1highres.jpg" width="500" /> 
Figure 1.&#160;Forced exercise regimen timeline. This timeline details the important events of each phase of this exercise regimen during each week of the study. The pre-acclimation phase (weeks 1-2) involves experimenter handling and baseline locomotor activity. During the acclimation phase (weeks 3-4) all rats undergo 3 days of acclimation training where they sit on the stationary treadmill and then 10 days of acclimation training to the treadmill. A minimum of two rounds of exercise (1 round = 12 consecutive days) followed by a 2-week rest period is required during the exercise training phase (weeks 5-10). Behavioral and/or neurochemical measurements can be made during these rest periods. Furthermore, this regimen can be modified to include multiple rounds of exercise in this phase. Body weight is measured throughout all phases of the study on a weekly basis, and before (first session) and after (last session) each phase of this exercise regimen. Treadmill exercise training scores are assigned after all acclimation and exercise training sessions, and range from 1-4, with 4 being the highest possible score. Briefly, a training score of 4 is assigned when rats exercise the entire training session without assistance. Similarly, assign a training score of 3 when rats require minimal assistance (defined as: assistance for less than 25% of the time of the training session) from the experimenter. Assign a training score of 2 when rats require much assistance (defined as: assistance for greater than 25% of the time of the training session) from the experimenter during the exercise session. Finally, allocate a training score of 1 to rats that are noncompliant and fail to complete an exercise session.
<ol>
	<li>Upon arrival to the animal colony, separate and singly house all subjects into standard shoebox cages. Provide food and water ad libitum to subjects throughout the entire study.</li>
	<li>Maintain a reverse 12-hr light-dark cycle (lights on from 1800 to 0600 hr) in the animal colony, and allow subjects to acclimate to this cycle for a minimum of one&#160;week. Perform all behavioral experiments during the subject&#8217;s active (dark) cycle, and 1-2 hr prior to the light-dark cycle change.</li>
	<li>Beginning two&#160;weeks prior to any behavioral experiments, handle all test subjects for several minutes daily to familiarize the subject with the experimenter, and to decrease novelty-induced stress to unfamiliar environments, such as the locomotor chamber and the treadmill.</li>
	<li>Measure each subject&#8217;s body weight once a week, and immediately before (first session) and after (last session) each major interval of the exercise paradigm.</li>
</ol>
2. Baseline Locomotor Activity Assessments: Determining Forced Exercise Group Assignments
<ol>
	<li>Assess each subject&#8217;s spontaneous locomotor activity for 60 min/day for 5 consecutive days to establish baseline locomotor capabilities. Conduct locomotor activity sessions in automated open-field locomotor activity chambers consisting of a plexiglass box (45 x 45 x 20 cm3) with a grid of infrared beams mounted horizontally and vertically as suggested in the product manual.</li>
	<li>At the beginning of each day of the locomotor activity assessments, load, and set up the computer and software program connected to the open-field locomotor activity chambers in order to record the number of beam breaks (locomotor activity) during each session.</li>
	<li>Add approximately 2 cups of pine-chip bedding to the floor of the locomotor chamber prior to each session.</li>
	<li>Transport the subjects from the animal colony to the locomotor activity chambers in their home cages immediately prior to their locomotor activity session. Load subjects into their assigned locomotor chamber under a red light, and start the 60 min session on the computer once they have been placed into the chamber.</li>
	<li>Upon completion of the locomotor activity session, remove subjects from the locomotor chamber and return them to their home cage under red light. Immediately return the subjects back to the animal colony.</li>
	<li>Remove bedding from the chamber and clean the chamber walls and floor with 50% ethanol after each session.</li>
	<li>Repeat steps 2.3-2.6 for additional locomotor sessions each day as needed until all subjects have been tested. Conduct all locomotor activity sessions in the dark, during the animal&#8217;s active cycle, and 1-2 hr prior to the light-dark cycle change.</li>
	<li>To account for the possibility of habituation to the activity chambers, rotate each subject among the available chambers such that locomotor activity is measured in a different chamber from the previous day.
	<ol>
		<li>If multiple sessions need to be conducted in one day, change the order of testing such that subjects are tested in a different order than the previous session.</li>
	</ol>
	</li>
	<li>From the data generated by the software used to measure locomotor activity, determine each animal&#8217;s baseline locomotor activity with the following 5 locomotor parameters: total distance traveled (cm), horizontal activity (number of beam breaks), movement number (number of initiated movements), time spent moving (sec), and movement speed (cm/sec).
	<ol>
		<li>In order to assign exercise and nonexercise groups, calculate the mean value across all 5 sessions for each of the 5 locomotor parameters listed in step 2.9 above.</li>
	</ol>
	</li>
	<li>From these 5 parameters, determine exercise and nonexercise (control) groups such that an equal range of locomotor activity is represented in both groups. In this way, pair rats together based on similar movement capabilities, and assign one rat to the exercise group and one rat to the nonexercise group. Thus, for example, pair the two rats that exhibit the highest average of all 5 locomotor parameters together, and assign one rat to the exercise group and the other to the nonexercise group (group assignments are chosen at random). Repeat this process for the remaining subjects.
	<ol>
		<li>Maintain pairing throughout the entire forced exercise regimen and for all data analyses.</li>
	</ol>
	</li>
	<li>If the experimenter is interested in the effects of exercise on locomotor activity, measure post-exercise locomotor activity using the same procedures described in steps 2.1-2.8.1 beginning the day after the last treadmill exercise session. NOTE: If the investigator is interested and/or the automated locomotor activity software permits, examine anxiety-related measures (i.e., time spent in periphery vs. the center of activity chamber) to assess the relative anxiety of subjects during locomotor activity assessments.</li>
</ol>
3. Acclimation to the Treadmill
<ol>
	<li>Conduct all treadmill exercise-related procedures on a motorized rodent treadmill with lanes that are separated by clear plexiglass walls&#160;during the animal&#8217;s active cycle, and 1-2 hr prior to the light-dark cycle change.</li>
	<li>In place of the electrical shock coils located at the back of each lane, use a plexiglass backstop designed specifically to fit the treadmill so that subjects can continuously exercise without coming into contact with the electrical shock coils. To prevent the backstop from sliding during the training sessions, hold the backstop in place with a 1.5 in&#160;c-clamp.</li>
	<li>Due to the experimenter handling required for treadmill exercise training, conduct all treadmill exercise sessions with the lights on.</li>
	<li>Transport subjects in their home cage to the treadmill immediately prior to their treadmill exercise training session. When the treadmill is stationary, load rats onto the treadmill in their assigned lane by sliding up the backstop just enough that subjects can maneuver under the backstop. Slide the backstop back down to the resting position once the subject is situated on the treadmill belt. Do not start the session until all subjects have been placed in their assigned lane for that particular session.
	<ol>
		<li>During the first phase of acclimation, place each rat on one of the four lanes of the stationary treadmill (as described in step 3.4) for 5-10 min/day for 3 consecutive days. Increase the time of each session with each successive day (e.g., 5 min on day 1, 7 min on day 2, and 10 min on day 3) as the rats become familiar with the treadmill apparatus and to reduce the potential for novelty stress to the treadmill apparatus. Important: Do not place rats anywhere on the treadmill (e.g.,&#160;deactivated electrical shock coils) except the stationary belt at this stage.</li>
	</ol>
	</li>
	<li>During the second phase of acclimation training, place each rat on one lane of the stationary treadmill in front of the backstop. When all subjects are in place, turn the treadmill on to a slow walking speed (e.g., 6 m/min). Regardless of experimental grouping, train all rats to walk on the treadmill during this phase to ensure that any potential effects observed from the forced exercise regimen result from the exercise training and not simply from the ability to exercise.</li>
	<li>As the belt of the treadmill begins to roll, ensure that all rats are walking in the forward direction. Assist rats as necessary by orienting or gently prodding them until they are moving forward. During the acclimation training period, train rats to walk on the treadmill such that they continuously walk on the treadmill without assistance from the experimenter.
	<ol>
		<li>Acclimate all rats to the treadmill by gradually increasing the speed over a period of 5-10 min/day for 10 consecutive days. To further facilitate compliance to treadmill exercise, train the rats at low speeds (6-8 m/min) for 5-10 min during the first 5 acclimation sessions, and increase to more moderate speeds (9-10 m/min) for 5-10 min during the last 5 acclimation sessions.</li>
		<li>Ensure that all rats can maintain a speed of 9-10 m/min for 10 min by the last session of the acclimation training period.</li>
	</ol>
	</li>
	<li>Upon completion of the treadmill acclimation session, remove subjects from the treadmill in the same manner used to load subjects as described in step 3.4. Immediately return subjects to their home cage and transport them back to the animal colony.</li>
	<li>Wipe down each individual lane including the walls and treadmill belt with 50% ethanol after each individual treadmill exercise training session.</li>
	<li>Ascertain the exercise capabilities of each rat across the exercise sessions by assigning a treadmill exercise score at the conclusion of each daily session. Assign a training score of 4 when rats exercise the entire training session without assistance. Similarly, assign a training score of 3 when rats require minimal assistance (defined as: assistance for less than 25% of the time of the training session) from the experimenter. Assign a training score of 2 when rats require much assistance (defined as: assistance for greater than 25% of the time of the training session) from the experimenter during the exercise session. Finally, allocate a training score of 1 to rats that are noncompliant and fail to complete an exercise session. 
	NOTE: The exercise scoring system is adapted, in part, from other studies19.
	<ol>
		<li>Exclude rats that cannot complete the acclimation phase due to noncompliance and/or an injury that prevents subjects from exercising (e.g., this includes rats that earn a treadmill exercise training score of 1 for more than one&#160;consecutive day of acclimation training).</li>
	</ol>
	</li>
	<li>Average the treadmill scores across each training period (e.g.,&#160;acclimation training and exercise training) to determine the exercise capabilities of each subject. Ensure that all rats are able earn a treadmill exercise score of 4 during a training session by the end of the acclimation period.
	<ol>
		<li>If some rats are not compliant to the top exercise speeds maintained by others throughout a training session, adjust the speed for these rats so that they are able to continue exercising for the same amount of time but at a slower speed throughout the training sessions. In this instance, train slower rats in separate sessions and increase the speed as the subjects adjust to the slower speeds.</li>
	</ol>
	</li>
	<li>To avoid the potential for lane bias on the treadmill during treadmill exercise training, rotate each rat among the available lanes of the treadmill so that they are training in a different lane with each subsequent exercise session.</li>
</ol>
4. Treadmill Exercise Training
<ol>
	<li>Begin the exercise training sessions the day following the last acclimation training session, and continue exercising rats for 12 consecutive days. Conduct these sessions during the animal&#8217;s active cycle, and 1-2 hr prior to the light-dark cycle change.</li>
	<li>Follow the same set-up procedures for each treadmill exercise training session used during acclimation training, as described in steps 3.2 and 3.4.</li>
	<li>At the start of each session, turn on the treadmill to a lower, warm-up speed (8 m/min) than the training speed (9-11 m/min) that will be maintained throughout the remainder of the exercise training session. Continue with this warm-up speed for 5-10 min at the beginning of the session. Adjust the speed to 9-11 m/min for the remainder of the training session. Train subjects an average of 30 min each session for the entire 12 days of exercise training.</li>
	<li>After each exercise training session, assign a treadmill exercise score to all rats in the exercise group using the same exercise scoring system described in step 3.9. Do not assign a training score during the treadmill exercise training period to nonexercise rats.</li>
	<li>Conduct the exercise and nonexercise sessions separately. Place the nonexercise rats on the stationary treadmill for the same duration that their exercise cohort trained during each session.</li>
	<li>As described in step 3.11, rotate each rat among the available lanes of the treadmill so that they are training in a different lane with each subsequent exercise session.</li>
	<li>Upon completion of one round of exercise, rest subjects for 14 days. NOTE: This rest period was chosen based on the results from the pilot study described in Figures 2A and 2B.</li>
	<li>If desired, conduct various behavioral and/or neurochemical assessments at the end of the 12-day training period. Conversely, continue with subsequent rounds of exercise training following the 14 day rest period.</li>
</ol>

<ol>
	<li>Erickson, K. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise+training+increases+size+of+hippocampus+and+improves+memory.">Exercise training increases size of hippocampus and improves memory.</a> Proc. Natl. Acad. Sci. U.S.A. 108 (7), 3017-3022 (2011).</li><li>Zigmond, M. J., Cameron, J. L., Hoffer, B. J., Smeyne, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurorestoration+by+physical+exercise:+Moving+forward.">Neurorestoration by physical exercise: Moving forward.</a> Parkinsonis., and Related Dis. 18 (S1), S147-S150 (2012).</li><li>Savela, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+activity+at+midlife+and+health-related+quality+of+life+in+older+men.">Physical activity at midlife and health-related quality of life in older men.</a> Arch. Intern. Med. 170 (13), 1171-1172 (2010).</li><li>Ridgel, A. L., Vitek, J. L., Alberts, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forced,+not+voluntary,+exercise+improves+motor+function+in+Parkinson's+disease+patients.">Forced, not voluntary, exercise improves motor function in Parkinson's disease patients.</a> Neurorehabil. Neural Repair. 23 (6), 600-608 (2009).</li><li>Demirel, H. A., Serova, L., Sabban, E. L., Broxson, C. S., Powers, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+expression+of+catecholamine+biosynthetic+enzymes+following+exercise:+modulation+by+age.">Gene expression of catecholamine biosynthetic enzymes following exercise: modulation by age.</a> Neuroscience. 103 (3), 703-711 (2001).</li><li>Petzinger, G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+treadmill+exercise+on+dopaminergic+transmission+in+the+1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned+mouse+model+of+basal+ganglia+injury.">Effects of treadmill exercise on dopaminergic transmission in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse model of basal ganglia injury.</a> J. Neurosci. 27 (20), 5291-5300 (2007).</li><li>Yoon, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treadmill+exercise+suppresses+nigrostriatal+dopaminergic+neuronal+loss+in+6-hydroxydopamine-induced+Parkinson's+rats.">Treadmill exercise suppresses nigrostriatal dopaminergic neuronal loss in 6-hydroxydopamine-induced Parkinson's rats.</a> Neurosci. Lett. 423 (1), 12-17 (2007).</li><li>Collier, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aging-related+changes+in+the+nigrostriatal+dopamine+system+and+the+response+to+MPTP+in+nonhuman+primates:+Diminished+compensatory+mechanisms+as+a+prelude+to+parkinsonism.">Aging-related changes in the nigrostriatal dopamine system and the response to MPTP in nonhuman primates: Diminished compensatory mechanisms as a prelude to parkinsonism.</a> Neurobiol. Dis. 26 (1), 56-65 (2007).</li><li>Phelan, J. P., Austad, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selecting+animal+models+of+human+aging:+inbred+strains+often+exhibit+less+biological+uniformity+than+F1+hybrids.">Selecting animal models of human aging: inbred strains often exhibit less biological uniformity than F1 hybrids.</a> J. Gerontol. 49 (1), B1-B11 (1994).</li><li>Yurek, D. M., Hipkens, S. B., Hebert, M. A., Gash, D. M., Gerhardt, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+decline+in+striatal+dopamine+release+and+motoric+function+in+brown+Norway/Fischer+344+hybrid+rats.">Age-related decline in striatal dopamine release and motoric function in brown Norway/Fischer 344 hybrid rats.</a> Brain Res. 791 (1-2), 246-256 (1998).</li><li>Spangler, E. L., Waggie, K. S., Hengemihle, J., Roberts, D., Hess, B., Ingram, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+assessment+of+aging+in+male+Fischer+344+and+brown+Norway+rats+strains+and+their+F1+hybrid.">Behavioral assessment of aging in male Fischer 344 and brown Norway rats strains and their F1 hybrid.</a> Neurobiol. Aging. 15 (3), 319-328 (1994).</li><li>Salvatore, M. F., Pruett, B. S., Spann, S. L., Dempsey, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aging+reveals+a+role+for+nigral+tyrosine+hydroxylase+ser31+phosphorylation+in+locomotor+activity+generation.">Aging reveals a role for nigral tyrosine hydroxylase ser31 phosphorylation in locomotor activity generation.</a> PLoS One. 4 (1), (2009).</li><li>Pruett, B. S., Salvatore, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GFR+&#945;-1+receptor+expression+in+the+aging+nigrostriatal+and+mesoaccumbens+pathways.">GFR &#945;-1 receptor expression in the aging nigrostriatal and mesoaccumbens pathways.</a> J. Neurochem. 115 (3), 707-715 (2010).</li><li>Salvatore, M. F., Pruett, B. S., Dempsey, C., Fields, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+profiling+of+dopamine+regulation+in+substantia+nigra+and+ventral+tegmental+area.">Comprehensive profiling of dopamine regulation in substantia nigra and ventral tegmental area.</a> J. Vis. Exp. (66), e4171 (2012).</li><li>Salvatore, M. F., Pruett, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dichotomy+of+tyrosine+hydroxylase+and+dopamine+regulation+between+somatodendritic+and+terminal+field+areas+of+nigrostriatal+and+mesoaccumbens+pathways.">Dichotomy of tyrosine hydroxylase and dopamine regulation between somatodendritic and terminal field areas of nigrostriatal and mesoaccumbens pathways.</a> PLoS One. 7 (1), e29867 (2012).</li><li>Pruett, B. S., Salvatore, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nigral+GFR+&#945;-1+infusion+in+aged+rats+increases+locomotor+activity,+nigral+tyrosine+hydroxylase,+and+dopamine+content+in+synchronicity.">Nigral GFR &#945;-1 infusion in aged rats increases locomotor activity, nigral tyrosine hydroxylase, and dopamine content in synchronicity.</a> Mol. Neurobiol. 47 (3), 988-999 (2013).</li><li>Abercrombie, E. D., Zigmond, M. J., Bloom, ,. F. .. E., Kupfer, D. .. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+31:+Modification+of+central+categcholaminergic+systems+by+stress+and+injury:+Functional+significance+and+clinical+implications.">Chapter 31: Modification of central categcholaminergic systems by stress and injury: Functional significance and clinical implications.</a> Psychopharmacology: The Fourth Generation of Progress. 31, 355-361 (1995).</li><li>Ong, , et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurobiological+consequences+of+acute+footshock+stress;+effects+on+tyrosine+hydroxylase+phosphorylation+and+activation+in+the+rat+brain+and+adrenal+medulla.">Neurobiological consequences of acute footshock stress; effects on tyrosine hydroxylase phosphorylation and activation in the rat brain and adrenal medulla.</a> J. Neurochem. , (2013).</li><li>Al-Jarrah, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endurance+exercise+promotes+cardiorespiratory+rehabilitation+without+neurorestoration+in+the+chronic+mouse+model+of+parkinsonism+with+severe+neurodegeneration.">Endurance exercise promotes cardiorespiratory rehabilitation without neurorestoration in the chronic mouse model of parkinsonism with severe neurodegeneration.</a> J. Neurosci. 149 (1), 28-37 (2007).</li><li>Dishman, R. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurobiology+of+exercise.">Neurobiology of exercise.</a> Obesity. 14 (3), 345-356 (2006).</li></ol>

The authors declare no conflicts of interest.

There is evidence to suggest that lifestyle strategies, such as exercise, may reduce the risk for chronic age-related diseases and their cardinal symptoms, including those of the neurodegenerative diseases like Alzheimer&#8217;s disease and PD20. The benefit of forced exercise on a treadmill, as opposed to voluntary exercise on a running wheel, is that the investigator can determine the frequency, the rate, and/or intensity of exercise, and duration of the exercise session. Thus, specific post-exercise effects...

Noninvasive lifestyle strategies that can either prevent or mitigate impairments to cognition and locomotion, both often associated with aging, are gaining traction as viable practices for maintaining health and well-being1,2. For example, moderate to rigorous exercise on a weekly and consistent basis in middle-aged men can significantly increase locomotor capabilities compared to similarly-aged peers with advancing age3. Furthermore, increasing evidence suggests that these lifestyle strategies, such as exercise, can mitigate or even reverse impairments associated with neurodegenerative diseases such as Parkinson&#8217;s disease (PD)4.
Efforts to understand the molecular mechanisms of aging-related impairments have also been directed toward identifying how noninvasive strategies, like exercise, reverse or attenuate the mechanisms that contribute to such impairments. Treadmill exercise is one such strategy being increasingly employed in models of PD5-7 and cognitive impairment1, wherein the mechanisms behind improvements in locomotor or cognitive function are still being determined. However, it is important to point out that aging is the neurobiological background of PD. Thus, for any potential translation of any exercise benefit in an animal model to be realized in the human condition it must take into consideration the neurobiological background of aging. For example, compensatory mechanisms that stave off locomotor impairment during PD progression could be impaired by the process of aging8. Thus, it stands to reason that exercise paradigms must be developed that not only consider the impact of aging in either the presence or absence of disease pathology, but that also could be initiated and maintained in aged rodents.
Therefore, in consideration of aging on the neurobiological background, the selection of the rat strain should be thoughtfully considered by the investigator. Several rat strains are available for aging studies, notably the Fischer 344 and the Brown-Norway/Fischer 344 F1 (BNF) hybrid. The commonly used Sprague Dawley rat (an outbred strain) is also amenable for such use, as it is commonly used in neurodegenerative disease models, such as the 6-hydroxydopamine PD model. Our laboratory uses both the Sprague Dawley and the BNF strains in aging and neurodegenerative disease work. In this report, we will present results highlighting our exercise protocols using both strains. For those investigators strictly focusing on age-related studies, the BNF strain offers some important advantages. First, it is comparatively less vulnerable to aging-related disorders (such as tumors) and has exceptional longevity (typical life span exceeds 30 months) in comparison to other strains. They also have less variability in a variety of physiological and behavioral outcomes9, and are also suitable to investigate approaches that intervene with the process of aging. Furthermore, experiments such as forced exercise demand considerable handling by the investigator, and the gentle disposition of the BNF strain is advantageous. Aging-related changes in striatal and midbrain dopamine tissue content, as well as locomotor activity changes are similar in BNF rats and primates10-11. Our laboratory also has extensive experience with characterizing and manipulating striatal and midbrain dopamine signaling as well as locomotor activity in the BNF strain12-16. Therefore, because the risk of other neurobiologically-based diseases increases with aging, animal models of neurodegenerative disease should consider the use of rodent strains with an extensive track record of use in aging studies.
Our protocol herein also addresses some critical issues that the investigator must consider in the interpretation of their results obtained from an exercise protocol. The rodent treadmill apparatus (the use of which we will highlight in this report), is typically equipped with electric shock coils at the back of each lane of the treadmill that can be deactivated. However when these electric shock coils are activated, a small footshock is delivered to the subject as it comes in contact with the coils. This strategy is often employed in exercise studies to facilitate compliance to treadmill exercise. This is a critical point for consideration, particularly for those investigators involved in behavioral studies that are influenced by dopamine- or norepinephrine-signaling. Electrical footshock is a physiological stressor, and its impact on both neurotransmitter systems is well-documented, with increased activation of tyrosine hydroxylase17-18. Thus, increased biosynthesis of either neurotransmitter could confound the interpretation of any exercise effect, making the investigator liable for interpreting whether any observed change in behavior after exercise is strictly due to the exercise regimen or the footshock stress. Importantly, the proposed forced exercise regimen does not employ the use of footshock at any point in the treadmill acclimation or exercise training periods.
Successful exercise regimens also require maximum compliance to exercise from test subjects. The employment of footshock in order to achieve compliance could confound interpretation of experimental outcomes when the dependent measure is related to neurotransmitter signaling that is influenced by footshock (as previously discussed). Thus, the challenge is to get rodents, and in particular aged rodents, to comply with an exercise regimen. A desirable goal of any exercise regimen is to achieve nearly 100% compliance, as this will reduce the number of animals necessary to complete the exercise regimen. Specifically, maximum compliance to exercise and interpretation of exercise regimen outcomes can be obtained in our exercise regimen as a result of several pre-exercise procedures including, 1) a reverse light-dark cycle that enables animals to exercise during their active (wake) cycle, 2) ensuring locomotor performance baselines are equal prior to segregation of control and exercise groups, and 3) introducing the test subjects to an acclimation period that gradually introduces them to the requirements of the exercise regimen. Here, the aforementioned experimental considerations and steps necessary to achieve nearly 100% compliance to treadmill exercise in an aged rodent (&#62;18 months of age) will be evaluated and presented. Finally, the environment associated with exercise may be stressful, and as such, present potential confounds to determine physiological effects specific to exercise. Our protocol also controls for the exposure to the potential stress-inducing environment of the treadmill by including the nonexercise group in every aspect of the acclimation phase (including modest treadmill running) and placing them on the stationary treadmill during the treadmill exercise training. Thus, this protocol aims to describe the measures necessary to determine the physiological impact of exercise alone.

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			<td colspan="6" height="41" rowspan="2" style="height:41px;width:815px;">Table of Specific Materials/Equipment</td>
		</tr>
		<tr height="21">
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name of Material/Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td colspan="3">Comments/Description</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;">Exer-4 Treadmill for Rats</td>
			<td>Columbus Instruments&#160;</td>
			<td>96157-2</td>
			<td colspan="3" style="width:321px;">Columbus has a variety of treadmills for animals with varying numbers of lanes, and other options such as metabolic measurements</td>
		</tr>
		<tr height="39">
			<td height="59" rowspan="2" style="height:59px;width:211px;">Animal Activity Meter: Opto-Varimex 4-Auto Track&#160;</td>
			<td rowspan="2">Columbus Instruments&#160;</td>
			<td rowspan="2">0170-R4</td>
			<td colspan="3" rowspan="2" style="width:321px;">Columbus has several options for activity chambers with varying arena sizes, beam spacing, and sensors</td>
		</tr>
		<tr height="20">
		</tr>
	</tbody>
</table>

getting to compliance in forced exercise in rodents: a critical standard to evaluate exercise impact in aging-related disorders and disease

There is a major increase in the awareness of the positive impact of exercise on improving several disease states with neurobiological basis; these include improving cognitive function and physical performance. As a result, there is an increase in the number of animal studies employing exercise. It is argued that one intrinsic value of forced exercise is that the investigator has control over the factors that can influence the impact of exercise on behavioral outcomes, notably exercise frequency, duration, and intensity of the exercise regimen. However, compliance in forced exercise regimens may be an issue, particularly if potential confounds of employing foot-shock are to be avoided. It is also important to consider that since most cognitive and locomotor impairments strike in the aged individual, determining impact of exercise on these impairments should consider using aged rodents with a highest possible level of compliance to ensure minimal need for test subjects. Here, the pertinent steps and considerations necessary to achieve nearly 100% compliance to treadmill exercise in an aged rodent model will be presented and discussed. Notwithstanding the particular exercise regimen being employed by the investigator, our protocol should be of use to investigators that are particularly interested in the potential impact of forced exercise on aging-related impairments, including aging-related Parkinsonism and Parkinson&#8217;s disease.

A diagram of the timeline of events in all three&#160;phases of the forced exercise regimen is shown in Figure 1. In addition to reversing the light-dark cycle, daily handling prior to any experimental testing, and stage 1 of acclimation training, where subjects sit on the stationary treadmill for 5-10 min/day for 3 consecutive days, were implemented to increase compliance to the forced exercise regimen. These procedures were added to the protocol in order to minimize stress associated with novel environ...

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Getting to Compliance in Forced Exercise in Rodents: A Critical Standard to Evaluate Exercise Impact in Aging-related Disorders and Disease

Exercise may alleviate behavioral impairments associated with neurodegenerative diseases. Studies of the mechanisms underlying exercise-mediated effects have increased in disease models, but the neurobiological background accompanying these diseases, specifically aging, is likely not considered. Here, we illustrate measures to increase the likelihood of a successful exercise paradigm in aged rats.

There is a major increase in the awareness of the positive impact of exercise on improving several disease states with neurobiological basis; these ...

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Research

JoVE Journal

Behavior

14.1K Views.  Louisiana State University Health Sciences Center. Exercise may alleviate behavioral impairments associated with neurodegenerative diseases. Studies of the mechanisms underlying exercise-mediated effects have increased in disease models, but the neurobiological background accompanying these diseases, specifically aging, is likely not considered. Here, we illustrate measures to increase the likelihood of a successful exercise paradigm in aged rats.

Video: Getting to Compliance in Forced Exercise in Rodents: A Critical Standard to Evaluate Exercise Impact in Aging-related Disorders and Disease

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals and humans. However, many animal models of depression were developed in males and are not applicable or effective in studies of postpartum females. Recent studies have reported significant effects of chronic social stress during lactation, an ethologically relevant and effective stressor, on maternal behavior, growth, and behavioral neuroendocrinology. This manuscript will describe this chronic social stress paradigm using repeated exposure of a lactating dam to a novel male intruder, and the assessment of the behavioral, physiological, and neuroendocrine effects of this model. Chronic social stress (CSS) is a valuable model for studying the effects of stress on the behavior and physiology of the dam as well as her offspring and future generations. The exposure of pups to CSS can also be used as an early life stress that has long term effects on behavior, physiology, and neuroendocrinology.

This article describes the use of chronic resident intruder social stress as an ethologically relevant paradigm to model postpartum depression and anxiety in lactating rodents.

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals ...

The Crossmodal Congruency Task as a Means to Obtain an Objective Behavioral Measure in the Rubber Hand Illusion Paradigm

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden hand is touched. If the viewed and felt touches are given at the same time then this is sufficient to induce the compelling experience that the rubber hand is one's own hand. The RHI can be used to investigate exactly how the brain constructs distinct body representations for one's own body. Such representations are crucial for successful interactions with the external world. To obtain a subjective measure of the RHI, researchers typically ask participants to rate statements such as "I felt as if the rubber hand were my hand". Here we demonstrate how the crossmodal congruency task can be used to obtain an objective behavioral measure within this paradigm.
The variant of the crossmodal congruency task we employ involves the presentation of tactile targets and visual distractors. Targets and distractors are spatially congruent (i.e. same finger) on some trials and incongruent (i.e. different finger) on others. The difference in performance between incongruent and congruent trials - the crossmodal congruency effect (CCE) - indexes multisensory interactions. Importantly, the CCE is modulated both by viewing a hand as well as the synchrony of viewed and felt touch which are both crucial factors for the RHI.
The use of the crossmodal congruency task within the RHI paradigm has several advantages. It is a simple behavioral measure which can be repeated many times and which can be obtained during the illusion while participants view the artificial hand. Furthermore, this measure is not susceptible to observer and experimenter biases. The combination of the RHI paradigm with the crossmodal congruency task allows in particular for the investigation of multisensory processes which are critical for modulations of body representations as in the RHI.

We demonstrate how an objective measure can be employed in the widely employed rubber hand illusion paradigm. This measure is obtained by modifying the well-established crossmodal congruency task. This task allows the investigation of multisensory processes which are critical for modulations of body representations as in the rubber hand illusion.

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden ...

A Procedure to Study the Effect of Prolonged Food Restriction on Heroin Seeking in Abstinent Rats

In human drug addicts, exposure to drug-associated cues or environments that were previously associated with drug taking can trigger relapse during abstinence. Moreover, various environmental challenges can exacerbate this effect, as well as increase ongoing drug intake.
The procedure we describe here highlights the impact of a common environmental challenge, food restriction, on drug craving that is expressed as an augmentation of drug seeking in abstinent rats.
Rats are implanted with chronic intravenous i.v. catheters, and then trained to press a lever for i.v. heroin over a period of 10-12 days. Following the heroin self-administration phase the rats are removed from the operant conditioning chambers and housed in the animal care facility for a period of at least 14 days. While one group is maintained under unrestricted access to food (sated group), a second group (FDR group) is exposed to a mild food restriction regimen that results in their body weights maintained at 90% of their nonrestricted body weight. On day 14 of food restriction the rats are transferred back to the drug-training environment, and a drug-seeking test is run under extinction conditions (i.e.&#160;lever presses do not result in heroin delivery).
The procedure presented here results in a highly robust augmentation of heroin seeking on test day in the food restricted rats. In addition, compared to the acute food deprivation manipulations we have used before, the current procedure is a more clinically relevant model for the impact of caloric restriction on drug seeking. Moreover, it might be closer to the human condition as the rats are not required to go through an extinction-training phase before the drug-seeking test, which is an integral component of the popular reinstatement procedure.

A procedure that allows a demonstration of robust augmentation of drug seeking in food-restricted rats is described. Following heroin self-administration training, rats go through an abstinence period, in a drug-free environment, during which they are mildly food restricted. Drug seeking is then tested in the drug-associated environment.

In human drug addicts, exposure to drug-associated cues or environments that were previously associated with drug taking can trigger relapse during ...

Uncovering Beat Deafness: Detecting Rhythm Disorders with Synchronized Finger Tapping and Perceptual Timing Tasks

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson&#8217;s disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder).

Behavioral tasks that allow for the assessment of perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) are presented. Synchronization of finger tapping to the beat of an auditory stimuli and detecting rhythmic irregularities provides a means of uncovering rhythm disorders.

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here ...

Assessment of Murine Exercise Endurance Without the Use of a Shock Grid: An Alternative to Forced Exercise

Using laboratory mouse models, the molecular pathways responsible for the metabolic benefits of endurance exercise are beginning to be defined. The most common method for assessing exercise endurance in mice utilizes forced running on a motorized treadmill equipped with a shock grid. Animals who quit running are pushed by the moving treadmill belt onto a grid that delivers an electric foot shock; to escape the negative stimulus, the mice return to running on the belt. However, avoidance behavior and psychological stress due to use of a shock apparatus can interfere with quantitation of running endurance, as well as confound measurements of postexercise serum hormone and cytokine levels. Here, we demonstrate and validate a refined method to measure running endurance in na&#239;ve C57BL/6 laboratory mice on a motorized treadmill without utilizing a shock grid. When mice are preacclimated to the treadmill, they run voluntarily with gait speeds specific to each mouse. Use of the shock grid is replaced by gentle encouragement by a human operator using a tongue depressor, coupled with sensitivity to the voluntary willingness to run on the part of the mouse. Clear endpoints for quantifying running time-to-exhaustion for each mouse are defined and reflected in behavioral signs of exhaustion such as splayed posture and labored breathing. This method is a humane refinement which also decreases the confounding effects of stress on experimental parameters.

A method to assess exercise endurance in laboratory mice without the use of a shock grid is demonstrated. This method is a humane refinement that can decrease the confounding effects of stress on experimental parameters.

Using laboratory mouse models, the molecular pathways responsible for the metabolic benefits of endurance exercise are beginning to be defined. The most ...

A Procedure to Observe Context-induced Renewal of Pavlovian-conditioned Alcohol-seeking Behavior in Rats

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate drug-seeking behavior and prompt relapse in abstinent drug users. We have developed a procedure to study the behavioral and neural processes that mediate the impact of context on alcohol-seeking behavior in rats. Following acclimation to the taste and pharmacological effects of 15% ethanol in the home cage, male Long-Evans rats receive Pavlovian discrimination training (PDT) in conditioning chambers. In each daily (Mon-Fri) PDT session, 16 trials each of two different 10 sec auditory conditioned stimuli occur. During one stimulus, the CS+, 0.2 ml of 15% ethanol is delivered into a fluid port for oral consumption. The second stimulus, the CS-, is not paired with ethanol. Across sessions, entries into the fluid port during the CS+ increase, whereas entries during the CS- stabilize at a lower level, indicating that a predictive association between the CS+ and ethanol is acquired. During PDT each chamber is equipped with a specific configuration of visual, olfactory and tactile contextual stimuli. Following PDT, extinction training is conducted in the same chamber that is now equipped with a different configuration of contextual stimuli. The CS+ and CS- are presented as before, but ethanol is withheld, which causes a gradual decline in port entries during the CS+. At test, rats are placed back into the PDT context and presented with the CS+ and CS- as before, but without ethanol. This manipulation triggers a robust and selective increase in the number of port entries made during the alcohol predictive CS+, with no change in responding during the CS-. This effect, referred to as context-induced renewal, illustrates the powerful capacity of contexts associated with alcohol consumption to stimulate alcohol-seeking behavior in response to Pavlovian alcohol cues.

A procedure to study the capacity of an alcohol associated environmental context to trigger the renewal of alcohol-seeking behavior in rats is described.

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate ...

Ultrasound Images of the Tongue: A Tutorial for Assessment and Remediation of Speech Sound Errors

Diagnostic ultrasound imaging has been a common tool in medical practice for several decades. It provides a safe and effective method for imaging structures internal to the body. There has been a recent increase in the use of ultrasound technology to visualize the shape and movements of the tongue during speech, both in typical speakers and in clinical populations. Ultrasound imaging of speech has greatly expanded our understanding of how sounds articulated with the tongue (lingual sounds) are produced. Such information can be particularly valuable for speech-language pathologists. Among other advantages, ultrasound images can be used during speech therapy to provide (1) illustrative models of typical (i.e.&#160;&#34;correct&#34;) tongue configurations for speech sounds, and (2) a source of insight into the articulatory nature of deviant productions. The images can also be used as an additional source of feedback for clinical populations learning to distinguish their better productions from their incorrect productions, en route to establishing more effective articulatory habits.
Ultrasound feedback is increasingly used by scientists and clinicians as both the expertise of the users increases and as the expense of the equipment declines. In this tutorial, procedures are presented for collecting ultrasound images of the tongue in a clinical context. We illustrate these procedures in an extended example featuring one common error sound, American English /r/. Images of correct and distorted /r/ are used to demonstrate (1) how to interpret ultrasound images, (2) how to assess tongue shape during production of speech sounds, (3), how to categorize tongue shape errors, and (4), how to provide visual feedback to elicit a more appropriate and functional tongue shape. We present a sample protocol for using real-time ultrasound images of the tongue for visual feedback to remediate speech sound errors. Additionally, example data are shown to illustrate outcomes with the procedure.

Ultrasound imaging can be used to display the shape and movements of the tongue in real time during speech. The images can be used to determine the nature of speech sound errors. Visual feedback of the tongue can be used to facilitate improvements in speech sound production in clinical populations.

Diagnostic ultrasound imaging has been a common tool in medical practice for several decades. It provides a safe and effective method for imaging ...

Supramaximal Intensity Hypoxic Exercise and Vascular Function Assessment in Mice

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by international guidelines for patients suffering from cardiovascular diseases, more specifically, lower extremity artery diseases, where the patients' walking capacity is considerably altered, affecting their quality of life. 
Traditionally, both low continuous exercise and interval training have been used. Recently, supramaximal training has also been shown to improve athletes' performances via vascular adaptations, amongst other mechanisms. The combination of this type of training with hypoxia could bring an additional and/or synergic effect, which could be of interest for certain pathologies. Here, we describe how to perform supramaximal intensity training sessions in hypoxia on healthy mice at 150% of their maximal speed, using a motorized treadmill and a hypoxic box. We also show how to dissect the mouse in order to retrieve organs of interest, particularly the pulmonary artery, the abdominal aorta, and the iliac artery. Finally, we show how to perform ex vivo vascular function assessment on the retrieved vessels, using isometric tension studies.

High-intensity training in hypoxia is a protocol that has been proven to induce vascular adaptations potentially beneficial in some patients and to improve athletes&#39; repeated sprint ability. Here, we test the feasibility of training mice using that protocol and identify those vascular adaptations using ex vivo vascular function assessment.

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by ...

Home-Based Prescribed Pulmonary Exercise in Patients with Stable Chronic Obstructive Pulmonary Disease

As a systemic disease, chronic obstructive pulmonary disease (COPD) affects the respiratory system, inducing restless and exercise dyspnea. It also impacts exercise capacity and forms a vicious circle in which it further aggravates the condition of patients and accelerates disease progression. As a functional holistic exercise, traditional Chinese exercises (TCE) play an important role in the rehabilitation of COPD on the basis of adjusting the breath and performing coordinated movements. This study investigates the effects of prescribed pulmonary exercises (which are modified from TCE) on exercise capacity of upper and lower limbs, endurance exercise capacity, and quality of life in stable COPD patients. The goal is to determine the accessibility of these prescribed exercises in COPD rehabilitation. Participants are randomly divided into a non-exercise control group (CG) or prescribed pulmonary exercise group (PG) at a ratio of 1: 1. The PG receives intervention for 60 min twice per day, 7 days a week, for a total of 3 months. The intensity is measured using the Borg category-ratio 10 scale and with a heart-rate monitor. Then, an exercise capacity test and quality of life questionnaire are scheduled at 1 week before and after the formal intervention. After 3 months of intervention, the 30 s arm curl test, 30 s sit-to-stand test, 6 min walking test, and quality of life show significant improvement in COPD patients (p &#60; 0.05). These findings indicate that prescribed pulmonary exercises can be applied as alternative, convenient, and effective home- and community-based exercises for stable COPD patients.

Presented here is a protocol to investigate the effects of home-based prescribed pulmonary exercise in stable chronic obstructive pulmonary disease (COPD) patients, which is modified based on traditional Chinese exercises according to dyspnea and limited exercise capacity observed in COPD patients.

As a systemic disease, chronic obstructive pulmonary disease (COPD) affects the respiratory system, inducing restless and exercise dyspnea. It also ...

Impact of High-intensity Interval Exercise and Moderate-Intensity Continuous Exercise on the Cardiac Troponin T Level at an Early Stage of Training

An elevation in cardiac troponin T (cTnT), as a highly specific biomarker of cardiomyocyte damage, after moderate-intensity continuous exercise (MCE) has been described. The exercise-induced cTnT response distorts the diagnostic role of the cTnT assay. Although high-intensity interval exercise (HIE) is growing in popularity and concerns remain about its safety, available data related to cTnT release after HIE is limited, which hampers the use of HIE as a health intervention. Here, we present three representative HIE protocols [traditional HIE (repeated 4 min cycling at 90% V&#775;O2max interspersed with 3 min rest, 200 kJ/session); sprint interval exercise (SIE, repeated 1 min cycling at 120% V&#775;O2max interspersed with 1.5 min rest, 200 kJ/session); and repeated sprint exercise (RSE, 40 x 6 s all-out sprints interspersed with 9 s rest)] and one representative MCE protocol (continuous cycling exercise at an intensity of 60% V&#775;O2max, 200 kJ/session). Forty-seven sedentary, overweight young women were randomly assigned to one of four groups (HIE, SIE, RSE, and MCE). Six bouts of respective exercise were performed by every single group, with each being 48 h apart. Meanwhile, for four groups, the duration of the entire testing period was identical, being 10 days. Before and after the first and final exercise bouts, an assessment was conducted of cTnT. The current study provides a frame of reference giving a clear picture of how a specific exercise session affects the circulating cTnT concentration at the early stage of training. The information may assist with clinical interpretations of post-exercise cTnT elevation and guide the prescription of exercise, especially for HIE.

Here, we present protocols of high-intensity interval and moderate-intensity continuous exercise to observe the response of circulating cardiac troponin T (cTnT) concentration to acute exercise over 10 days. The information may assist with clinical interpretations of post-exercise cTnT elevation and guide the prescription of exercise.

An elevation in cardiac troponin T (cTnT), as a highly specific biomarker of cardiomyocyte damage, after moderate-intensity continuous exercise (MCE) has ...