We wish to thank the animal care personnel at the University at Buffalo Animal Laboratory Animal Facility. This research was supported by a Veteran Affairs Rehabilitation Research and Development Grant RX001066 and the Indian Trail Foundation.

All studies and experimental protocols were approved by and in compliance with guidelines of the University at Buffalo and VA Western New York Animal Care and Use Committees.
1. Experiment Setup and General Advice
NOTE: A total of twenty-four female mice on a C57BL/6J background were used in this protocol starting at 23&#160;months of age. The mice carried&#160;a conditional SIRTloxp-exon4-loxp mutation29, however, this was not induced in this experiment.
<ol>
	<li>Ensure that mice receive permanent identifiers such as ear tags, RFID chips, or tail tattoos. 
	NOTE: It is recommended to also use temporary markings (e.g., permanent marker to mark tails) for quick identification during assessment periods.</li>
	<li>Clean the treadmill with 0.25-0.5% bleach (v/v) or 70% (v/v) ethanol at the end of the day or to remove feces or urine between experimental trials. Dry solutions completely before initiating a new trial. 
	NOTE: Ethanol may increase wear to the treadmill belt. It is recommended that the treadmill be cleaned between each run if working with group-housed male mice in order to minimize in cage fighting. It is recommended to perform treadmill assessments at the same time of day at each time point in longitudinal studies30,31,32, and if other assessments are being performed, the order should remain the same. The investigator running the experiment should also be blind to the group designations of the mice.</li>
</ol>
2. Acclimatizing Mice to Treadmill Apparatus
NOTE: Initiate acclimatization of mice 1&#160;month prior to baseline experiments.
<ol>
	<li>Set up the initial training program using the treadmill software (v3.4.7) in Manual mode (Figure 1 and Table 1).
	<ol>
		<li>Open the treadmill software. Then, click on the file and open the experiment.</li>
		<li>Input the values indicated in Table 1 on the Manual tab (Figure 1) under Acclimation.</li>
		<li>Input the session number as 1, the number of active channels as 1 to 6 depending on the number of mice, the number of visits to the grid as 10, and the number of shocks as 20. 
		NOTE: Shock intensity for this initial run is set at level 1 (0.46&#160;mA).</li>
	</ol>
	</li>
	<li>Set the inclination of the treadmill to 0&#176; (flat).</li>
	<li>Hold mice by the tail when placing in the treadmill and place mice directly on the belt to avoid starting mice on the shock grid.</li>
	<li>Use a brush or tongue depressor to keep mice away from the shock grid when training or assessment begins. Nudge mice to begin running to avoid unintended shocks.</li>
	<li>After each mouse is given the initial training program, repeat the program as above with the shock intensity increased to level 2 (0.59&#160;mA) with at least 15&#160;min between trainings.</li>
	<li>One to two days after the initial training program administer the uphill treadmill acclimatization.
	<ol>
		<li>Open the treadmill software. Then click on the file and then open the experiment.</li>
		<li>Input the values on the Basic tab as indicated in Table 2 under Acclimation.</li>
		<li>Under Shock Detection, input the session number as 1, the number of active channels as 1 to 6 depending on the number of mice, the number of visits to the grid as 10, and the number of shocks as 20.</li>
		<li>Click on the Profile Mode tab (Figure 2) and for Step 1, input a start speed of 0&#160;m/min and an end speed of 5&#160;m/min with a period of 5&#160;s.
		<ol>
			<li>Add a warm up step 2 with a start speed of 5&#160;m/min and end speed of 5&#160;m/min for 30&#160;seconds. Add a transition step that starts at 5&#160;m/min and an end speed of 6&#160;m/min for 5&#160;s.</li>
			<li>Add a test speed step that starts at 6&#160;m/min and ends at 6&#160;m/min for 20&#160;s. Add a transition step that starts at 6&#160;m/min and ends at 5&#160;m/min.</li>
			<li>Add a recovery interval that starts at 5&#160;m/min and ends at 5&#160;m/min for 20&#160;s (Figure 2).</li>
		</ol>
		</li>
		<li>Repeat step 2.6.4 to add test speed steps as indicated in Table 2 under acclimation.</li>
	</ol>
	</li>
	<li>Two weeks prior to baseline assessments, continue acclimatization by providing two treadmill flat aerobic capacity assessments as described in section 3, given on consecutive days.</li>
	<li>One to two days after the second endurance training, provide two treadmill uphill anaerobic capacity assessments as described in section 4, given on the same day with a minimum of 30&#160;min between trainings.</li>
</ol>
3. Flat Continuous Treadmill Assessment
<ol>
	<li>Create a treadmill program as described in step 2.1, using values indicated in Table 1 under Assessment. Under Shock Detection, set the session number as 1, the number of active channels as 1 to 6 depending on the number of mice, the number of visits to the grid as 10, and the number of shocks as 20.</li>
	<li>Monitor the mice throughout the trial and remove mice from the instrument that reach the endpoint criteria. 
	NOTE: This step is to avoid mice inadvertently touching the shock grid of neighboring mice and affecting data. Parameters include the total time on belt, the distance travelled, and the shocks to visits ratio. It is recommended to perform two assessments at each time point, separated by at least one day between assessments.</li>
</ol>
4. Uphill Interval Treadmill Assessment
<ol>
	<li>Create a treadmill program as described in step 2.6, using values indicated in Table 2 under Assessment. Under Shock Detection, set the session number as 1, the number of active channels as 1 to 6 depending on the number of mice, the number of visits to the grid as 5, and the number of shocks as 10.</li>
	<li>Set the interval field in the treadmill program to 0.5. 
	NOTE: This allows for data points to be collected every second instead of every minute, which aids in identifying the speed at endpoint for each mouse. The program will automatically stop after the 50&#160;m/min stage due to software limitations. Parameters include the time on belt, the distance travelled, and the test speed of the last successfully completed stage before endpoint. The latter is used for determining baseline intensity for the HIIT regimen described in step 5. It is recommended to perform two assessments per time point, separated by at least 30&#160;min.</li>
</ol>
5. Short session High Intensity Interval Training
<ol>
	<li>Set the treadmill uphill (25&#176;) and remove the plastic cover.</li>
	<li>Determine the intensity for each mouse. Use the speed of the last successfully completed stage (Step 4.5) and find the intensity group and corresponding Base, Sprint, and Dash speeds using Table 3.</li>
	<li>Open the treadmill software and click on file to create a new program.
	<ol>
		<li>Click on the Profile Mode tab and for Step 1, input a start speed of 0&#160;m/min and an end speed as indicated under Base speed as indicated in Table 3 with a period of 5&#160;s.</li>
		<li>Add a warm up step 2 with a start speed at Base speed and end speed at Base speed for 180&#160;s.</li>
		<li>Input 3 intervals each with 1) a transition step that goes from Base to Sprint for 5&#160;s, 2) an step at Sprint speed for 60s, 3) a transition step that goes from &#8220;sprint&#8221; to Base over 5&#160;s, and 4) a step for a recovery interval at Base speed for 60&#160;s.</li>
		<li>Add a transition step that goes from Base to Sprint speed over 5&#160;s and a final step that goes from Sprint to Dash speed over 60&#160;s. 
		NOTE: Programs can be saved, modified, and reloaded.</li>
	</ol>
	</li>
	<li>Perform exercise three days a week with at least one day of rest between sessions (i.e., Monday, Wednesday, Friday).</li>
	<li>Rewrite exercise programs to increase Base, Sprint, and Dash speeds 1&#160;m/min every two weeks. 
	NOTE: No electric shocks are given during the exercise.</li>
	<li>Motivate mice to run using a makeup brush (recommended) or tongue depressor to lightly motivate mice that fall near or on the shock grid. If a mouse does not respond retry in 5&#160;s, then 10&#160;s, and then retry every 30&#160;s or during a recovery interval until the end of the session. 
	NOTE: consider removing mice from the study that do not run on the treadmill at any intensity or are unable to complete the first three intervals at the intensity defined for the lowest intensity group (Table 3)</li>
	<li>Move mice that cannot be motivated to complete the first three intervals in two consecutive exercise sessions to lower intensity groups (Table 3).</li>
	<li>Move mice that do not require motivation in two consecutive exercise sessions to higher intensity groups (Table 3).</li>
	<li>Take sedentary control mice in cages place beside the treadmill as it runs. Alternatively, sedentary controls can be placed in the lanes of a non-moving treadmill for 10&#160;min.</li>
</ol>

The authors have nothing to disclose.

Benefits from short sessions are a key aspect of high intensity interval training that captures scientific and public interest. However, animal studies rarely investigate HIIT regimens that are 10 min or less. Here, we describe a protocol for a 10 min short session HIIT uphill treadmill exercise regimen that enhanced treadmill performance in aged female mice and which we previously have shown to increase physical performance in aged male mice17. A strength of our protocol is that in addition to th...

Regular exercise is effective at preventing or delaying many age-associated diseases such as sarcopenia and frailty1,2,3,4. However, less than 15% of those 65 and older meet recommendations of 150 min a week of moderate intensity exercise plus strength 
training5,6. As the lack of time and lengthy sessions are common barriers to exercise, high intensity interval training (HIIT) is emerging as an alternative to traditional regimens. HIIT features multiple short bursts of intense activity that are interspersed with brief periods of active recovery, and there has been recent interest in identifying the shortest regimens that still yield beneficial outcomes. Such studies include 3 day a week regimens featuring total session times of 4 min7, 2-3 min8, 1.5 min9, a single min10, and even 40 s11.
Likewise, there has been substantial interest in HIIT animal models. A majority of studies used mice12,13,14,15,16,17,18,19,20,21 or rats22,23,24,25 and were performed using a treadmill, although a few others used swimming protocols26,27,28. A majority of these studies use VO2max to set the initial intensity of the exercise13,14,19,21,24. Additionally, although an often described benefit of HIIT is having shorter regimens, almost all of these identified studies feature regimens that last 30&#160;min or longer11,12,13,14,15,18,19,21, with the exception of one with a slightly longer than 10&#160;min regimen20, and another with 19 min across three different intensities16. To our knowledge, there are no reported animal studies that examine a 10&#160;min or less HIIT regimen, or tailor the regimen to individual animals, with the exception of our published study17 that serves as the basis for this protocol.
Here, we describe a protocol for HIIT in aged mice designed to model individualized, short session (&#8804;10&#160;min) variants used recently in human studies7,8,9,10,11. The method includes a 10 min regimen on an inclined (25&#176;) treadmill with a 3 min warm up, and four 1 min intervals at high intensity, interspersed with three 1 min active recovery segments. Advantages of the protocol include greater clinical relevance as it features strategies for tailoring intensity to individual animals, setting intensities that are not based on VO2max, thereby avoiding the need for metabolic treadmills, and modular design whereby the number of intervals and timings are easily adjustable. Additionally, within this protocol we provide instructions for two strategies for treadmill assessment, which include flat continuous and uphill interval, to examine endurance. Using these methods, we extend our previous findings that short session HIIT increased functional capacity in aged male mice17, and now demonstrate HIIT increases treadmill performance in aged female mice.

<table><tbody><tr><td>Exer-3/6 Open Treadmill w/ Shock, Detection, auto-calibration and PC Interface/Software</td><td>Columbus Instruments</td><td>1055-SDRM</td><td>The Columbus Instruments 3/6 treadmill allow up to 6 mice or 3 rats simultaneously.&lt;br/&gt; The device comes with controllers to allow manual control of treadmill belt speed and shock intensity, or connections to a computer and software to run and control these elements.&amp;nbsp;</td></tr><tr><td>Bleach</td><td>Varies</td><td>Varies</td><td>0.25-0.5% Bleach solution (V/V) is used to clean the treadmill belt between sessions</td></tr><tr><td>Ethanol</td><td>Varies</td><td>Varies</td><td>70% ethanol solution (V/V) can alternatively be used to clean treadmill belt between runs and sesions.</td></tr><tr><td>Make-up Brush (large)</td><td>Varies</td><td>Varies</td><td>A make-up brush provides a soft surface and ample length to motivate mice to continue exercise.</td></tr></tbody></table>

short session high intensity interval training and treadmill assessment in aged mice

High intensity interval training (HIIT) is emerging as a therapeutic approach to prevent, delay, or ameliorate frailty. In particular short session HIIT, with regimens less than or equal to 10 min is of particular interest as several human studies feature routines as short as a few minutes a couple times a week. However, there is a paucity of animal studies that model the impacts of short session HIIT. Here, we describe a methodology for an individually tailored and progressive short session HIIT regimen of 10 min given 3 days a week for aged mice using an inclined treadmill. Our methodology also includes protocols for treadmill assessment. Mice are initially acclimatized to the treadmill and then given baseline flat and uphill treadmill assessments. Exercise sessions begin with a 3 min warm-up, then three intervals of 1 min at a fast pace, followed by 1 min at an active recovery pace. Following these intervals, the mice are given a final segment that starts at the fast pace and accelerates for 1 min. The HIIT protocol is individually tailored as the speed and intensity for each mouse are determined based upon initial anaerobic assessment scores. Additionally, we detail the conditions for increasing or decreasing the intensity for individual mice depending on performance. Finally, intensity is increased for all mice every two weeks. We previously reported in this protocol enhanced physical performance in aged male mice and here show it also increases treadmill performance in aged female mice. Advantages of our protocol include low administration time (about 15 min per 6 mice, 3 days a week), strategy for individualizing for mice to better model prescribed exercise, and a modular design that allows for the addition or removal of the number and length of intervals to titrate exercise benefits.

A total of twenty-five female mice were bred and aged in house. The C57BL/6J background mice carried&#160;a SIRT1loxp-exon4-loxp mutation29; however, this&#160;conditional knockout was not induced and therefore all mice exhibited full length Sirtuin1 (data not shown). At 24 months of age, mice were assessed for treadmill endurance and uphill sprint capacity prior to and after the administration of two months of HIIT exercise (n = 14), or remaini...

Watch this Scientific Journal Video about Short Session High Intensity Interval Training and Treadmill Assessment in Aged Mice at JoVE.com

Short Session High Intensity Interval Training and Treadmill Assessment in Aged Mice

Short session (&#8804;10 min) high intensity interval training (HIIT) is emerging as an alternative to longer exercise modalities, yet the shorter variants are rarely modeled in animal studies. Here, we describe a 10 min, 3 day a week, uphill treadmill HIIT protocol that enhances physical performance in male and female aged mice.

High intensity interval training (HIIT) is emerging as a therapeutic approach to prevent, delay, or ameliorate frailty. In particular short session HIIT, ...

short-session-high-intensity-interval-training-treadmill-assessment

Research

JoVE Journal

Behavior

9.7K Views.  University at Buffalo and Research Service, Veterans Affairs Western New York Healthcare System. Short session (≤10 min) high intensity interval training (HIIT) is emerging as an alternative to longer exercise modalities, yet the shorter variants are rarely modeled in animal studies. Here, we describe a 10 min, 3 day a week, uphill treadmill HIIT protocol that enhances physical performance in male and female aged mice.

Video: Short Session High Intensity Interval Training and Treadmill Assessment in Aged Mice

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.

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 ...

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 ...

The Treadmill Fatigue Test: A Simple, High-throughput Assay of Fatigue-like Behavior for the Mouse

Fatigue is a prominent symptom in many diseases and disorders and reduces quality of life for many people. The lack of clear pathogenesis and failure of current interventions to adequately treat fatigue in all patients leaves a need for new treatment options. Despite the therapeutic need and importance of preclinical research in helping identify promising novel treatments, few preclinical assays of fatigue are available. Moreover, the most common preclinical assay used to assess fatigue-like behavior, voluntary wheel running, is not suitable for use with some strains of mice, may not be sensitive to drugs that reduce fatigue, and has relatively low throughput. The current protocol describes a novel, non-voluntary preclinical assay of fatigue-like behavior, the treadmill fatigue test, and provides evidence of its efficacy in detecting fatigue-like behavior in mice treated with a chemotherapy drug known to cause fatigue in humans and fatigue-like behavior in animals. This assay may be a beneficial alternative to wheel running, as fatigue-like behavior and potential interventions can be assessed in a greater number of mice over a shorter time frame, thus permitting faster discovery of new therapeutic options.

Fatigue is a common, undertreated and frequently poorly-understood symptom in many diseases and disorders. New preclinical assays of fatigue may help to improve current understanding and future treatment of fatigue. To that end, the current protocol provides a novel means of measuring fatigue-like behavior in the mouse.

Fatigue is a prominent symptom in many diseases and disorders and reduces quality of life for many people. The lack of clear pathogenesis and failure of ...

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 ...

A Method to Study the Impact of Chemically-induced Ovarian Failure on Exercise Capacity and Cardiac Adaptation in Mice

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in post-menopausal women has not been adequately studied. Accordingly, we investigated the impact of voluntary cage-wheel exercise and forced treadmill exercise on cardiac adaptation in menopausal mice. The most commonly used inducible model for mimicking menopause in women is the ovariectomized (OVX) rodent. However, the OVX model has a few dissimilarities from menopause in humans. In this study, we administered 4-vinylcyclohexene diepoxide (VCD) to female mice, which accelerates ovarian failure as an alternative menopause model to study the impact of exercise in menopausal mice. VCD selectively accelerates the loss of primary and primordial follicles resulting in an endocrine state that closely mimics the natural progression from pre- to peri- to post-menopause in humans. To determine the impact of exercise on exercise capacity and cardiac adaptation in VCD-treated female mice, two methods were used. First, we exposed a group of VCD-treated and untreated mice to a voluntary cage wheel. Second, we used forced treadmill exercise to determine exercise capacity in a separate group VCD-treated and untreated mice measured as a tolerance to exercise intensity and endurance.

Two exercise paradigms were tested on a newly developed chemically induced menopausal mouse model to examine the impact of menopause on exercise capacity and cardiac adaption to exercise.

The risk of cardiovascular disease (CVD) increases in post-menopausal women, yet, the role of exercise, as a preventative measure for CVD risk in ...

Medicine

Tracking Individual Running Metrics in Mice Using a Voluntary Wheel Running Protocol that Minimizes Social Isolation

Voluntary wheel running (VWR) in rodents is used to evaluate performance and endurance and to simulate exercise. In contrast to other exercise paradigms that require aversive stimulus to induce active movement, wheel running is voluntary. VWR generally consists of placing a running wheel inside the mouse home cage. However, analyzing exercise parameters can typically only be conducted when mice are individually housed, while overall cage effects can be reported when mice are group-housed. Therefore, the current models force experimenters to choose between measuring individual exercise parameters in single-housed mice or measuring group effects in group-housed mice; depending on the research question and model, this could be limiting. 
Therefore, the goal of this method is to demonstrate a protocol that assesses VWR in a mouse model by quantifying running parameters in individual mice, with minimal isolation. We report on device design, preoperative preparations, and experiment setup. Results of a 6-week training protocol using this VWR model suggest it provides sufficient stimulus to increase spatial object recognition memory, comparable to the clinical effect of exercise. This simple and inexpensive model facilitates investigation into the effect of VWR on multiple measurements of wheel activity, minimizing factors that could limit or affect experimental outcomes.

This protocol describes an effective voluntary wheel-running model that can be implemented in various research contexts. Unlike other voluntary running models, this method avoids isolation housing while tracking running metrics in individual mice.

Voluntary wheel running (VWR) in rodents is used to evaluate performance and endurance and to simulate exercise. In contrast to other exercise paradigms ...

Accumulated High-intensity Interval Training Protocol: A New Approach to Study Health Markers in Wistar Rats

High-Intensity Interval Training (HIIT) and accumulated exercises are two time-efficient programs to improve health in humans and animal models. However, to date, there are no studies on whether HIIT performed in an accumulated fashion is as effective as a traditional HIIT performed with single daily sessions in improving health markers. This paper presents the effects of a new HIIT protocol, called accumulated HIIT, on body weight gain, maximal oxygen consumption (VO2max), and cardiac hypertrophy in young Wistar rats. 
Sixty-day-old male Wistar rats were assigned to three groups: untrained (UN; n = 16), HIIT performed with single daily sessions (1-HIIT; n = 16), and HIIT performed with three daily sessions (3-HIIT; n = 16). Body weight and VO2max were recorded before and after the training period. The VO2max measurements were taken using a metabolic analyzer at the maximal running velocity (Vmax). The training was performed for both HIIT groups five days per week over eight weeks with the same weekly progression of the exercise intensity (85-100% Vmax). The 1-HIIT group performed single daily sessions (6 bouts of 1 min interspersed with 1 min of passive recovery). The 3-HIIT group performed three daily sessions (2 bouts of 1 min interspersed with 1 min of passive recovery with an interval of 4 h between bouts). After the last VO2max test, the rats were euthanized, and their hearts were harvested and weighed.
The results showed that 3-HIIT had similar beneficial effects to 1-HIIT in preventing body weight gain, improving VO2max, and inducing cardiac hypertrophy. These findings reveal for the first time the efficacy of an accumulated HIIT protocol on the health markers of young Wistar rats. This new HIIT protocol may be more feasible than traditional HIIT protocols as exercise can be split into very short sessions throughout a day in this new approach.

Here, we present accumulated high-intensity interval training (HIIT) protocols, which may be a more feasible and time-efficient strategy than traditional HIIT protocols.

High-Intensity Interval Training (HIIT) and accumulated exercises are two time-efficient programs to improve health in humans and animal models. However, ...

Real-Time Electrocardiogram Monitoring During Treadmill Training in Mice

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. However, in certain cardiac diseases such as inherited arrhythmia syndromes, e.g., arrhythmogenic cardiomyopathy (ACM) or myocarditis, physical exercise may have negative effects on the heart leading to a proarrhythmogenic substrate production. Currently, the underlying molecular mechanisms of exercise-related proarrhythmogenic remodeling are largely unknown, thus it remains unclear which frequency, duration, and intensity of exercise can be considered safe in the context of disease(s).
The proposed method allows to study proarrhythmic/antiarrhythmic effects of physical exercise by combining treadmill training with real-time monitoring of the ECG. Implantable telemetry devices are used to continuously record the ECG of freely moving mice over a period of up to 3 months both at rest and during treadmill training. Data acquisition software with its analysis modules is used to analyze basic ECG parameters such as heart rate, P wave duration, PR interval, QRS interval, or QT duration at rest, during and after training. Furthermore, heart rate variability (HRV) parameters and occurrence of arrhythmias are evaluated. In brief, this manuscript describes a step-by-step approach to experimentally explore exercise induced effects on cardiac electrophysiology, including potential proarrhythmogenic remodeling in mouse models.

Electrocardiogram (ECG) is the key variable to understanding cardiac electrophysiology. Physical exercise has beneficial effects but may also be harmful in the context of cardiovascular diseases. This manuscript provides a method of recording real-time ECG during exercise, which can serve to investigate its effects on cardiac electrophysiology in mice.

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. ...

Versatility of Protocols for Resistance Training and Assessment Using Static and Dynamic Ladders in Animal Models

Resistance training is a physical exercise model with profound benefits for health throughout life. The use of resistance exercise animal models is a way to gain insight into the underlying molecular mechanisms that orchestrate these adaptations. The aim of this article is to describe exercise models and training protocols designed for strength training and evaluation of resistance in animal models and provide examples. In this article, strength training and resistance evaluation are based on ladder climbing activity, using static and dynamic ladders. These devices allow a variety of training models as well as provide precise control of the main variables which determine resistance exercise: volume, load, velocity, and frequency. Furthermore, unlike resistance exercise in humans, this is a forced exercise. Thus, aversive stimuli must be avoided in this intervention to preserve animal welfare. Prior to implementation, a detailed design is necessary, along with an acclimatization and learning period. Acclimatization to training devices, such as ladders, weights, and clinical tape, as well as to the manipulations required, is necessary to avoid exercise rejection and to minimize stress. At the same time, the animals are taught to climb up the ladder, not down, to the resting area on the top of the ladder. Resistance evaluation can characterize physical strength and permit adjusting and quantifying the training load and the response to training. Furthermore, different types of strength can be evaluated. Regarding training programs, with appropriate design and device use, they can be sufficiently versatile to modulate different types of strength. Furthermore, they should be flexible enough to be modified depending on the adaptive and behavioral response of the animals or the presence of injuries. In conclusion, resistance training and assessment using ladders and weights are versatile methods in animal research.

The present protocol describes resistance training and testing using static and dynamic ladders in animal models.

Resistance training is a physical exercise model with profound benefits for health throughout life. The use of resistance exercise animal models is a way ...

Biology

A Simple and Inexpensive Running Wheel Model for Progressive Resistance Training in Mice

Previously developed rodent resistance-based exercise models, including synergistic ablation, electrical stimulation, weighted-ladder climbing, and most recently, weighted-sled pulling, are highly effective at providing a hypertrophic stimulus to induce skeletal muscle adaptations. While these models have proven invaluable for skeletal muscle research, they are either invasive or involuntary and labor-intensive. Fortunately, many rodent strains voluntarily run long distances when given access to a running wheel. Loaded wheel running (LWR) models in rodents are capable of inducing adaptations commonly observed with resistance training in humans, such as increased muscle mass and fiber hypertrophy, as well as stimulation of muscle protein synthesis. However, the addition of moderate wheel load either fails to deter mice from running great distances, which is more reflective of an endurance/resistance training model, or the mice discontinue running nearly entirely due to the method of load application. Therefore, a novel high-load wheel running model (HLWR) has been developed for mice where external resistance is applied and progressively increased, enabling mice to continue running with much higher loads than previously utilized. Preliminary results from this novel HLWR model suggest it provides sufficient stimulus to induce hypertrophic adaptations over the 9 week training protocol. Herein, the specific procedures to execute this simple yet inexpensive progressive resistance-based exercise training model in mice are described.

This procedure describes a translatable progressive loaded running wheel resistance training model in mice. The primary advantage of this resistance training model is that it is entirely voluntary, thus reducing stress for the animals and the burden on the researcher.

Previously developed rodent resistance-based exercise models, including synergistic ablation, electrical stimulation, weighted-ladder climbing, and most ...