Thank you to the "Thim van der Laan" Foundation, Landquart, Switzerland, for the financial support. We also thank Thomas Konzett, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland, and Ursula M. K&#252;ng, University College Physiotherapy, Landquart, Switzerland, for their assistance during the experiment, as well as Alexander Masselink, for his assistance with English.

Ethics Statement: The Swiss Cantonal Ethical Committee of Zurich approved this protocol (KEK-ZH No. 2015-0113)
1. Recruitment of Participants
<ol>
	<li>Recruit participants through social media and flyers.</li>
	<li>Screen and include participants who are university students between 18 and 30 years of age. Ensure that they can perform endurance sports a minimum of two times (minimum total time: 2 h) and a maximum of three times (maximum total time: 3 h) per week, that they are free of current pain symptoms, and that they have had no injuries in the torso or lower extremities in the previous 12 months.</li>
	<li>Screen and exclude participants if they are allergic to cold (including Raynaud&#39;s disease), suffer from cardiovascular diseases or any other disease, must take any medication, are pregnant, or have skeletal deviations.</li>
</ol>
2. Familiarization with the Testing Protocol (Day 1)
<ol>
	<li>One week prior to the experiment, instruct the participants to perform a maximum of 5 CMJs on a jump mat (see the Table of Materials), with a 1-min resting period between each jump12,27. Instruct them to start from an upright position and to place their hands on their hips to eliminate arm swing. Permit a self-determined range of motion and contraction time during the CMJs.</li>
	<li>Instruct the participants to return to the laboratory one week after the familiarization session in a pain-free state and without having performed exhaustive exercise 48 h prior to the experiment. 
	NOTE: The pain-free and exhaustion-free state will be assessed as the baseline measurements.</li>
</ol>
3. Baseline Measurements (Day 2)
<ol>
	<li>Measure the standing body-height, body-weight, and estimated lower-body fat percentage of the participants three times in a row and calculate the mean values28.</li>
	<li>Have the participants assess their individual DOMS of both frontal thighs on a visual analog scale (VAS; 0-10 cm)5 during a 3-s lasting squat position29 (90&#176; knee angle). Ask the participants: &#34;How sore are your frontal thighs?&#34; Record the number from the VAS in mm. 
	NOTE: The far-left endpoint of the scale (0 cm) represents &#34;no soreness,&#34; and the far-right endpoint of the scale (10 cm) represents &#34;severe soreness.&#34;</li>
	<li>Have the participants rate their individual perceived exertion in an upright standing position using a 6-20 BORG scale30. Ask the participants: &#34;What is your actual level of perceived exertion?&#34; Record the verbally communicated number. 
	NOTE: The participants rate this verbally by telling the researcher one number between 6 (no perceived exertion) and 20 (maximum perceived exertion).</li>
	<li>Have the participants perform a maximum of 3 CMJs12,27 (as practiced during the familiarization session), with a 30-s pause between the three jumps, on a jump mat. 
	NOTE: The jump heights from the CMJs are indirectly recorded as the time in flight by the jump mat system.</li>
	<li>Use the highest jump and calculate the peak power output (PPO) according to the formula used in the study of Sayers et al.31: 
	PPO = (60.7 x jump height [cm]) + (45.3 x body weight [kg]) &#8211; 2,055 
	NOTE: The subjective ratings and the objective assessments will be repeated directly after the recovery application (0 h) and 24, 48, and 72 h after the exhaustive jump protocol (see below).</li>
	<li>Randomly assign the participants either to the cold group or to the thermoneutral group by drawing lots.</li>
</ol>
4. Exhaustive Jump Protocol
<ol>
	<li>Directly after the randomization, instruct the participants to get ready to perform the exhaustive jump protocol, without any warm-up exercises.</li>
	<li>Have two researchers visually inspect the quality of the jumps (maximum jump performance and touching the ground with the fingers after each jump), verbally correct, and encourage the participants during the jump protocol.</li>
	<li>Have the participants perform a maximum of 3 x 30 CMJs or until exhaustion at their own speeds, with a 30 s pause between the sets. 
	NOTE: Allow the participants to sit down and drink water during the pause.</li>
</ol>
5. Recovery Application
<ol>
	<li>After the exhaustive jump protocol, have a blinded researcher apply either a cold cuff or a thermoneutral cuff (see the Table of Materials) to a participant&#39;s thighs.
	<ol>
		<li>Place the participant in supine position and apply both cuffs directly onto the skin of each thigh to ensure full contact, but using minimum pressure to avoid any compression effects. 
		NOTE: Optionally, refill the tank of a continuous programmable cooling and heating device with a ready-to-use, non-toxic lubrication mixture consisting of propylene glycol and demineralized water to the maximum level.</li>
	</ol>
	</li>
	<li>Start the device and apply either the cold modality (+ 8 &#176;C) or the thermoneutral modality (+ 32 &#176;C) for a duration of 20 min. 
	NOTE: Instruct the participants not to report information about their temperature sensation.</li>
	<li>Take off the thigh cuffs after the application and shut down the device.</li>
</ol>
6. Non-invasive Recovery Assessment After 0 h
NOTE: The researcher performing all recovery assessments should not be informed if the participants received a cold- or a thermoneutral-cuff application.
<ol>
	<li>Have the participants rate their individual DOMS and RPE, as described in steps 3.2 and 3.3.</li>
	<li>Have the participants perform a maximum of 3 CMJs and calculate the PPO, as described in steps 3.4 and 3.5.</li>
	<li>Instruct the participants to maintain their daily habits but to refrain from alcohol, sport, and recreational training during the 72 h recovery period. Instruct the participants to return to the laboratory exactly 24, 48, and 72 h after the exhaustive jump protocol.</li>
</ol>
7. Non-invasive Recovery Assessment After 24 h (Day 3), 48 h (Day 4), and 72 h (Day 5)
<ol>
	<li>Have the participants rate their individual DOMS and RPE, as described in steps 3.2 and 3.3.</li>
	<li>Have the participants perform a maximum of 3 CMJs and calculate the PPO, as described in steps 3.4 and 3.5. 
	NOTE: The protocol ends after the 72 h follow-up period (Day 5).</li>
</ol>

None of the authors have competing or conflicting interests.

This protocol describes the execution of a standardized exhaustive jump protocol, a cryotherapy recovery modality, and a non-invasive assessment of recovery characteristics. The protocol of this randomized controlled trial provides several advantages compared to traditionally performed methods in the field of post-exercise recovery studies. Previous studies showed that jump protocols consisting of 100 jumps are a valid method to induce local muscle damage36,37. Ferreira-Junior et al. used a jump protocol consisting of five sets of 20 drop-jumps from a 0.6 m box, with 2 min rest intervals between the sets, to induce muscle damage of the frontal thighs36. Whereas other traditional exhaustion protocols require expensive or mechanical devices38, the current protocol induced muscular exhaustion without the use of any mechanical device. Researchers do not need to buy or rent expensive devices to induce muscular exhaustion or damage to the frontal thighs.
The recovery interventions were applied using a continuous programmable cooling and heating device that can deliver cold or heat to a specific area of the body. Two thigh cuffs were applied around both thighs in supine position for 20 min. Although CWI is one of the most promising methods of enhancing recovery39, the transportation and the necessary amount of water are two challenging factors for the execution of this intervention. Furthermore, to guarantee the ideal water temperature, an additional person is needed to monitor and add ice.
An advantage of the present protocol is the use of an automated and portable cooling and heating device that ensures a constant temperature during the cuff application. Another advantage of the described protocol is the possibility of assessing subjective and objective recovery characteristics without taking blood samples from the participants. The subjective ratings, DOMS (VAS; 0-10 cm) and RPE (BORG; 6-20), used after an exhaustive protocol have been described in numerous published articles24,40,41,42. The assessment of CMJs, as presented in the present protocol, shows a high test-retest reliability (intra-class correlation coefficient (ICC) between 0.48 and 0.88) and validity25,26.
There are some critical steps within the protocol that may present potential sources of error. Two researchers must observe, verbally encourage, and correct the participants during the exhaustive CMJs (3 x 30). The objective monitoring of maximum CMJs may be ensured using accelerometers or linear transducers. Another critical step is the application of the two thigh cuffs. To avoid any compression effects43,44, the cuffs must be wrapped around each thigh with a minimum level of pressure. The application of the cuffs with a minimum of pressure might take a couple of practice runs to master.
The present protocol has some limitations. The 30 s rest period between the sets of the exhaustive jump protocol is very short, and the cardiovascular impact is very high. Another limitation is the ready-to-use lubrication mixture for the recovery modality. It is important to take into account that the heat capacity of this lubrication mixture (i.e., propylene glycol and demineralized water) is slightly lower than that of normal water. The familiarization session of 5 jumps might be too small when the study population is not as physically active as described in the present protocol.
Finally, the assessment of CMJs presents the opportunity to assess objective recovery characteristics. Bishop et al. demonstrated a cheap and practicable method to assess jump height with the mobile-based app &#34;My Jump,&#34; which has been shown to be a reliable method for measuring this variable45,46. However, Rowsell et al. indicated that no apparent reductions in CMJ height during a 5-day follow-up period could be observed after exhaustive soccer tournament matches24. Rupp et al. observed similar results after an exhaustive endurance test34. These results are in line with the results of the presents study, showing that the assessment of CMJ height might not be sensitive enough to measure the amount of muscular exhaustion.
In this protocol, the cold application temperature was set at 8 &#176;C, whereas the temperature of the thermoneutral application was set at 32 &#176;C. It has been demonstrated that cold water temperatures are normally &#8804;20 &#176;C and that thermoneutral water temperatures have a range from 24 &#176;C to &#60;36 &#176;C47. It is important to consider that the amount of adipose tissue significantly affects the tissue cooling rate, with thicker skinfolds requiring longer application times48. Researchers should modify the cooling temperature and application duration according to their research populations.
Future studies should consider that the assessment of the maximum voluntary contractions of the knee extensors might be a more sensitive assessment of objective recovery characteristics compared to CMJs49. For this protocol to be effective, it is crucial that the participants perform a familiarization session for the CMJs. Future studies using a different study population than that described here should increase the number of jumps to guarantee a familiarization effect. Additionally, future studies might increase the resting time between the exhaustive CMJs to guarantee maximum jump performance, which would then be unaffected by the high cardiovascular demand.
In conclusion, the current exhaustive jump protocol is an easy and practical way to induce muscular exhaustion of the frontal thighs without the use of any mechanical devices. By combining subjective (i.e., DOMS and RPE) and objective (i.e., CMJ and PPO) parameters, recovery can be investigated without taking any blood samples during a 72 h recovery period. The local post-exercise cryotherapy application can be carried out nearly anywhere and guarantees constant cooling temperatures.

Cryotherapy is a frequently used treatment modality to enhance post-exercise recovery1,2. The vasoconstrictive response of the body after exposure to cold is one of the main mechanisms of reducing the inflammatory processes3,4. Frequently used cryotherapy procedures include cold packs5 or cuffs6, cold air7,8, cold water immersion (CWI)9, whole-body cryotherapy10,11, cooling vests12, and internal cooling methods13,14. However, internal cooling procedures have demonstrated contradictory results15,16.
Controversial results on recovery have also been reported after external local cooling applications. One study reported that post-exercise cryotherapy did not enhance vertical jump performance (VJP) but decreased subjective ratings of perceived exertion (RPE) compared to active recovery procedures17. In contrast, another study demonstrated that cryotherapy had no influence on post-exercise subjective RPE5. A meta-analysis by Hohenauer et al. indicated that post-exercise cryotherapy might have a positive effect on subjective recovery characteristics, with no effects on inflammatory markers1.
The majority of studies that determine the effects of cryotherapy on recovery involve expensive devices to induce muscular exhaustion7,18,19 and invasive procedures to assess blood plasma markers or cytokines19,20,21. The aims of the present protocol are to induce similar muscular exhaustion without the use of any device and to provide a non-invasive method to determine the effects of local cryotherapy cuff application on subjective and objective recovery characteristics. The rationale behind this method is that it provides a tool for other researchers or coaches to induce muscular exhaustion, without using any expensive devices; to implement local cooling strategies based on this protocol; and to measure both subjective and objective recovery, without using invasive methods. This might help to assess subjective and objective recovery characteristics following an exhaustive jump protocol in a sport-realistic, non-invasive setting.
Published studies show that validated, non-invasive methods for evaluating subjective recovery characteristics (i.e., delayed-onset muscle soreness (DOMS)22 and RPE)23 have been used with success. Countermovement jump (CMJ) performance17,24, with a high test-retest reliability25,26, can also be used as a non-invasive method to assess objective recovery characteristics.

<table><tbody><tr><td>Anthropometer 100</td><td>GPM Anthropometric Instruments (URL:http://www.seritex.com/)</td><td>not applicable</td><td>Standing body-height can be measured with other accurate systems</td></tr><tr><td>TANITA TBF 611</td><td>TANITA corporation (URL:http://www.tanita.com/en/)</td><td>500314M</td><td></td></tr><tr><td>Just Jump System</td><td>Probotics Inc. (URL:http://www.probotics.org/JustJump/JustJump.htm)&amp;nbsp;</td><td>23056311</td><td>This system includes the jump mat and the jump height recorder. Other accurate systems, measuring vertical jump height may be used alternatively</td></tr><tr><td>Zamar Therapy ZT Clinic</td><td>Zamar Medical D.O.O (URL:http://www.zamar.care/)</td><td>MG675AA00F</td><td>This is a continous programmable cooling and heating device</td></tr><tr><td>Zamar Large Thigh Thermal Wraps</td><td>Zamar Care (URL:http://www.zamar.care/sport.html)</td><td>not applicable</td><td>2 Thigh Thermal Wraps are needed</td></tr><tr><td>Zamar Equi Insulated 4.7 m &quot;V&quot;t Pipe &amp;amp; Safety Connector</td><td>http://www.zamar.care/clinic.html</td><td>ZAM-1ACS410</td><td></td></tr><tr><td>Non Tox Freeze 4</td><td>Pakelo Motor Oil S.r.l. (URL:http://www.pakelo.com/)</td><td>0131.34.47</td><td></td></tr><tr><td>Schmerzskala (VAS 0 - 10 cm)</td><td>Mundipharma Medical Company (URL:http://www.mundipharma.ch/index.php?id=73)</td><td>not applicable</td><td></td></tr><tr><td>BORG scale (6 - 20)</td><td>URL:http://www.mesics.de/fileadmin/user/literature/Allgemein/Borg-Skala_Loellgen.pdf</td><td>not applicable</td><td></td></tr></tbody></table>

non-invasive assessments of subjective and objective recovery characteristics following an exhaustive jump protocol

Fast recovery after strenuous exercise is important in sports and is often studied via cryotherapy applications. Cryotherapy has a significant vasoconstrictive effect, which seems to be the leading factor in its effectiveness. The resulting enhanced recovery can be measured by using both objective and subjective parameters. Two commonly measured subjective characteristics of recovery are delayed-onset muscle soreness (DOMS) and ratings of perceived exertion (RPE). Two important objective recovery characteristics are countermovement jump (CMJ) performance and peak power output (PPO). Here, we provide a detailed protocol to induce muscular exhaustion of the frontal thighs with a self-paced, 3 x 30 countermovement jump protocol (30-s rest between each set). This randomized controlled trial protocol explains how to perform local cryotherapy cuff application (+ 8 &#176;C for 20 min) and thermoneutral cuff application (+ 32 &#176;C for 20 min) on both thighs as two possible post-exercise recovery modalities. Finally, we provide a non-invasive protocol to measure the effects of these two recovery modalities on subjective (i.e., DOMS of both frontal thighs and RPE) and objective recovery (i.e., CMJ and PPO) characteristics 24, 48, and 72 h post-application. The advantage of this method is that it provides a tool for researchers or coaches to induce muscular exhaustion, without using any expensive devices; to implement local cooling strategies; and to measure both subjective and objective recovery, without using invasive methods. Limitations of this protocol are that the 30 s rest period between sets is very short, and the cardiovascular demand is very high. Future studies may find the assessment of maximum voluntary contractions to be a more sensitive assessment of muscular exhaustion compared to CMJs.

The schematic representation of the test protocol is presented in Figure 1. This section illustrates that this protocol was successful at inducing muscular exhaustion and at monitoring subjective and objective recovery characteristics during a 72 h follow-up period, without using invasive techniques (Figure 2 and Figure 3).
Goodall et al. studied DOMS in a 90&#176; squat position after a muscle damage protocol29. Likewise, the present study also assessed DOMS in this position. As described in previously published articles, the DOMS elevated directly after the recovery application (0 h) and after 48 h in both groups (Figure 2A)29,32. However, in both groups, these values did not return to baseline values after a 72 h recovery period32.
This protocol also allows for the observation of changes in overall perceived exertion (Figure 2B). In the present study, a 6-20 BORG scale was used as in the study of Rowsell et al.24. In accordance to the study of Minett et al., the RPE was elevated in both groups directly after the recovery application12. However, these values returned to baseline after 24 h in the thermoneutral group and remained at this level for up to 72 h. In the cold group, the RPE values increased again after 48 h and remained at this level for up to 72 h.
Figure 3A and Figure 3B show that the exhaustive jump protocol induced a decrease in jump height (CMJ) and PPO in both conditions directly after the recovery application (0 h)12,33. Both the jump height (CMJ) and PPO increased after 24 h and again decreased after 48 and 72 h in the cold and thermoneutral groups. These results are in line with previously published articles24,33,34.

<img alt="Figure 1" src="/files/ftp_upload/55612/55612fig1.jpg" /> 
Figure 1: Schematic representation of the test protocol. Downward-pointing arrows denote the time points when recovery characteristics were measured. DOMS = delayed-onset muscle soreness, RPE = rated perceived exertion, CMJ = countermovement jump, PPO = peak power output. This figure has been modified from Hohenauer et al.35. <a href="http://cloudflare.jove.com/files/ftp_upload/55612/55612fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<img alt="Figure 2" src="/files/ftp_upload/55612/55612fig2.jpg" /> 
Figure 2: Change in DOMS and RPE over time. (A) Delayed-onset muscle soreness (DOMS; (median &#177; interquartile ranges). A repeated-measures ANOVA revealed a time effect (P = 0.003) and a group effect (P = 0.03), but no group x time interaction (P = 0.89). Post-hoc differences between the groups were P &#62;0.05 for all time points. (B) Rated perceived exertion (RPE; median &#177; interquartile ranges). A repeated-measures ANOVA revealed a time effect (P &#60;0.001) and a group effect (P = 0.09), but no group x time interaction (P = 0.29). Post-hoc differences between the groups were P &#62;0.05 for all time points. * indicates a significant time effect (p &#60;0.05). # indicates significant differences from baseline values within groups (p &#60;0.05). This figure has been modified from Hohenauer et al.35. <a href="http://cloudflare.jove.com/files/ftp_upload/55612/55612fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/55612/55612fig3.jpg" /> 
Figure 3: Change in CMJ and PPO over time. (A) Jump height during countermovement jump (CMJ; mean &#177; SD). A repeated-measures ANOVA revealed a time effect (P &#60;0.001), but no group effect (P = 0.35) and time x group interaction (P = 0.35). Post-hoc differences between the groups were P &#62;0.05 for all time points. (B) Peak power output (PPO; mean &#177; SD). A repeated-measures ANOVA revealed a time effect (P &#60;0.001), but no group effect (P = 0.96) and time x group interaction (P = 0.35). Post-hoc differences between groups were P &#62;0.05 for all time points. * indicates a significant time effect (P &#60;0.05). This figure has been modified from Hohenauer et al.35. <a href="http://cloudflare.jove.com/files/ftp_upload/55612/55612fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Non-invasive Assessments of Subjective and Objective Recovery Characteristics Following an Exhaustive Jump Protocol at JoVE.com

Non-invasive Assessments of Subjective and Objective Recovery Characteristics Following an Exhaustive Jump Protocol

This protocol describes the procedure for non-invasive recovery assessments during a 72 h recovery period. This protocol induces muscular exhaustion of the frontal thighs using countermovement jumps and uses either local cold-cuff or thermoneutral-cuff application as a recovery modality.

Fast recovery after strenuous exercise is important in sports and is often studied via cryotherapy applications. Cryotherapy has a significant ...

non-invasive-assessments-subjective-objective-recovery

Research

JoVE Journal

Medicine

7.7K Views.  University of Applied Sciences and Arts of Southern Switzerland.  Dit protocol beschrijft de procedure voor niet-invasieve herstelbeoordeling tijdens een herstelperiode van 72 uur. Dit protocol stimuleert spieruitputting van de voorste dijen met behulp van tegenwaartse sprongen en gebruikt lokale koude manchet of thermoneutral-manchet applicatie als herstelmodaliteit. 

Video: Non-invasive Assessments of Subjective and Objective Recovery Characteristics Following an Exhaustive Jump Protocol

Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI

Spinal cord injury (SCI) is a debilitating disorder, which produces profound deficits in volitional motor control. Following medical stabilization, recovery from SCI typically involves long term rehabilitation. While recovery of walking ability is a primary goal in many patients early after injury, those with a motor incomplete SCI, indicating partial preservation of volitional control, may have the sufficient residual descending pathways necessary to attain this goal. However, despite physical interventions, motor impairments including weakness, and the manifestation of abnormal involuntary reflex activity, called spasticity or spasms, are thought to contribute to reduced walking recovery. Doctrinaire thought suggests that remediation of this abnormal motor reflexes associated with SCI will produce functional benefits to the patient. For example, physicians and therapists will provide specific pharmacological or physical interventions directed towards reducing spasticity or spasms, although there continues to be little empirical data suggesting that these strategies improve walking ability.
In the past few decades, accumulating data has suggested that specific neuromodulatory agents, including agents which mimic or facilitate the actions of the monoamines, including serotonin (5HT) and norepinephrine (NE), can initiate or augment walking behaviors in animal models of SCI. Interestingly, many of these agents, particularly 5HTergic agonists, can markedly increase spinal excitability, which in turn also increases reflex activity in these animals. Counterintuitive to traditional theories of recovery following human SCI, the empirical evidence from basic science experiments suggest that this reflex hyper excitability and generation of locomotor behaviors are driven in parallel by neuromodulatory inputs (5HT) and may be necessary for functional recovery following SCI. 
The application of this novel concept derived from basic scientific studies to promote recovery following human SCI would appear to be seamless, although the direct translation of the findings can be extremely challenging. Specifically, in the animal models, an implanted catheter facilitates delivery of very specific 5HT agonist compounds directly onto the spinal circuitry. The translation of this technique to humans is hindered by the lack of specific surgical techniques or available pharmacological agents directed towards 5HT receptor subtypes that are safe and effective for human clinical trials. However, oral administration of commonly available 5HTergic agents, such as selective serotonin reuptake inhibitors (SSRIs), may be a viable option to increase central 5HT concentrations in order to facilitate walking recovery in humans. Systematic quantification of how these SSRIs modulate human motor behaviors following SCI, with a specific focus on strength, reflexes, and the recovery of walking ability, are missing.
This video demonstration is a progressive attempt to systematically and quantitatively assess the modulation of reflex activity, volitional strength and ambulation following the acute oral administration of an SSRI in human SCI. Agents are applied on single days to assess the immediate effects on motor function in this patient population, with long-term studies involving repeated drug administration combined with intensive physical interventions.

This video demonstrates modulation of reflex activity, volitional strength and ambulation through clinical and quantitative assessments in individuals with motor incomplete SCI as a result of acute oral administration of a serotonin reuptake inhibitor (SSRI).

Spinal cord injury (SCI) is a debilitating disorder, which produces profound deficits in volitional motor control. Following medical stabilization, ...

Using Gold-standard Gait Analysis Methods to Assess Experience Effects on Lower-limb Mechanics During Moderate High-heeled Jogging and Running

A limited number of studies have explored lower-limb biomechanics during high-heeled jogging and running, and most studies have failed to clarify the wearing experience of subjects. This protocol describes the differences in lower-limb kinematics and ground reaction force (GRF) between experienced wearers (EW) and inexperienced wearers (IEW) during moderate high-heeled jogging and running. A three-dimensional (3D) motion analysis system with a configured force platform was used to synchronously capture lower-limb joint movements and GRF. 36 young females volunteered to participate in this study and were asked about high-heeled shoe-wearing experience, including frequency, duration, heel types, and heel heights. Eleven who had the experience of 3 to 6 cm heels for a minimum of three days per week (6 h per day) for at least two years and eleven who wore high heels less than twice per month participated. Subjects performed jogging and running at comfortable low and high speeds, respectively, with the right foot completely stepping onto a force platform when passing by along a 10 m walkway. EW and IEW adopted different biomechanical adaptations while jogging and running. IEW exhibited a generally larger range of joint movement, while EW showed a dramatically larger loading rate of GRF during running. Hence, further studies on the lower-limb biomechanics of high-heeled gait should strictly control the wearing experience of the subjects.

This study investigated lower-limb kinematics and ground reaction force (GRF) during moderate high-heeled jogging and running. Subjects were divided into groups of experienced wearers and inexperienced wearers. A three-dimensional motion analysis system with a configured force platform captured lower-limb joint movements and GRF.

A limited number of studies have explored lower-limb biomechanics during high-heeled jogging and running, and most studies have failed to clarify the ...

Behavior

A Novel Application of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.

We describe a new ultrasound-based vector tissue Doppler imaging technique to measure muscle contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities. This approach provides complementary measurements of dynamic muscle function and could lead to a better understanding of mechanisms underlying musculoskeletal disorders.

Ultrasound is an attractive modality for imaging muscle and tendon  motion during dynamic tasks and can provide a complementary methodological  approach ...

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers

Incremental exercise testing is the standard means of assessing cardiorespiratory capacity of endurance athletes. While the maximal rate of oxygen consumption is typically used as the criterion measurement in this regard, two metabolic breakpoints that reflect changes in the dynamics of lactate production/consumption as the work rate is increased are perhaps more relevant for endurance athletes from a functional standpoint. Exercise economy, which represents the rate of oxygen consumption relative to performance of submaximal work, is also an important parameter to measure for endurance-athlete assessment. Ramp incremental tests comprising a gradual but rapid increase in work rate until the limit of exercise tolerance is reached are useful for determining these parameters. This type of test is typically performed on a cycle ergometer or treadmill because there is a need for precision with respect to work-rate incrementation. However, athletes should be tested while performing the mode of exercise required for their sport. Consequently, swimmers are typically assessed during free-swimming incremental tests where such precision is difficult to achieve. We have recently suggested that stationary swimming against a load that is progressively increased (incremental tethered swimming) can serve as a &#34;swim ergometer&#34; by allowing sufficient precision to accommodate a gradual but rapid loading pattern that reveals the aforementioned metabolic breakpoints and exercise economy. However, the degree to which the peak rate of oxygen consumption achieved during such a protocol approximates the maximal rate that is measured during free swimming remains to be determined. In the present article, we explain how this rapidly incremented tethered-swimming protocol can be employed to assess the cardiorespiratory capacity of a swimmer. Specifically, we explain how assessment of a short-distance competitive swimmer using this protocol revealed that his rate of oxygen uptake was 30.3 and 34.8 mL&#8729;min-1&#8729;kg-1BM at his gas-exchange threshold and respiratory compensation point, respectively.

As opposed to measurement during free swimming, which presents inherent challenges and limitations, determination of important parameters of cardiorespiratory function for swimmers can be made using a more feasible and easier to administer tethered-swimming rapidly incremented protocol with gas exchange and ventilatory data collection.

Incremental exercise testing is the standard means of assessing cardiorespiratory capacity of endurance athletes. While the maximal rate of oxygen ...

Biochemistry

An Inertial Measurement Unit Based Method to Estimate Hip and Knee Joint Kinematics in Team Sport Athletes on the Field

Current athlete monitoring practice in team sports is mainly based on positional data measured by global positioning or local positioning systems. The disadvantage of these measurement systems is that they do not register lower extremity kinematics, which could be a useful measure for identifying injury-risk factors. Rapid development in sensor technology may overcome the limitations of the current measurement systems. With inertial measurement units (IMUs) securely fixed to body segments, sensor fusion algorithms and a biomechanical model, joint kinematics could be estimated. The main purpose of this article is to demonstrate a sensor setup for estimating hip and knee joint kinematics of team sport athletes in the field. Five male subjects (age 22.5 &#177; 2.1 years; body mass 77.0 &#177; 3.8 kg; height 184.3 &#177; 5.2 cm; training experience 15.3 &#177; 4.8 years) performed a maximal 30-meter linear sprint. Hip and knee joint angles and angular velocities were obtained by five IMUs placed on the pelvis, both thighs and both shanks. Hip angles ranged from 195&#176; (&#177; 8&#176;) extension to 100.5&#176; (&#177; 8&#176;) flexion and knee angles ranged from 168.6&#176; (&#177; 12&#176;) minimal flexion and 62.8&#176; (&#177; 12&#176;) maximal flexion. Furthermore, hip angular velocity ranged between 802.6 &#176;&#183;s-1 (&#177; 192 &#176;&#183;s-1) and -674.9 &#176;&#183;s-1 (&#177; 130 &#176;&#183;s-1). Knee angular velocity ranged between 1155.9 &#176;&#183;s-1 (&#177; 200 &#176;&#183;s-1) and -1208.2 &#176;&#183;s-1 (&#177; 264 &#176;&#183;s-1). The sensor setup has been validated and could provide additional information with regard to athlete monitoring in the field.&#160;This may help professionals in a daily sports setting to evaluate their training programs, aiming to reduce injury and optimize performance.

Monitoring athletes is essential for improving performance and reducing injury risk in team sports. Current methods to monitor athletes do not include the lower extremities. Attaching multiple inertial measurement units to the lower extremities could improve monitoring athletes in the field.

Current athlete monitoring practice in team sports is mainly based on positional data measured by global positioning or local positioning systems. The ...

A Multi-Modal Approach to Assessing Recovery in Youth Athletes Following Concussion

Concussion is one of the most commonly reported injuries amongst children and youth involved in sport participation. Following a concussion, youth can experience a range of short and long term neurobehavioral symptoms (somatic, cognitive and emotional/behavioral) that can have a significant impact on one&#8217;s participation in daily activities and pursuits of interest (e.g., school, sports, work, family/social life, etc.). Despite this, there remains a paucity in clinically driven research aimed specifically at exploring concussion within the youth sport population, and more specifically, multi-modal approaches to measuring recovery. This article provides an overview of a novel and multi-modal approach to measuring recovery amongst youth athletes following concussion. The presented approach involves the use of both pre-injury/baseline testing and post-injury/follow-up testing to assess performance across a wide variety of domains (post-concussion symptoms, cognition, balance, strength, agility/motor skills and resting state heart rate variability). The goal of this research is to gain a more objective and accurate understanding of recovery following concussion in youth athletes (ages 10-18 years). Findings from this research can help to inform the development and use of improved approaches to concussion management and rehabilitation specific to the youth sport community.

This article provides an overview of a multi-modal approach to assessing recovery following concussion in youth athletes. The described protocol uses pre- and post-concussion assessment of performance across a wide variety of domains and can inform the development of improved concussion rehabilitation protocols specific to the youth sport community.

Concussion is one of the most commonly reported injuries amongst children and youth involved in sport participation. Following a concussion, youth can ...

A Neuroscientific Approach to the Examination of Concussions in Student-Athletes

Concussions are occurring at alarming rates in the United States and have become a serious public health concern. The CDC estimates that 1.6 to 3.8 million concussions occur in sports and recreational activities annually. Concussion as defined by the 2013 Concussion Consensus Statement &#8220;may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an &#8216;impulsive&#8217; force transmitted to the head.&#8221; Concussions leave the individual with both short- and long-term effects. The short-term effects of sport related concussions may include changes in playing ability, confusion, memory disturbance, the loss of consciousness, slowing of reaction time, loss of coordination, headaches, dizziness, vomiting, changes in sleep patterns and mood changes. These symptoms typically resolve in a matter of days. However, while some individuals recover from a single concussion rather quickly, many experience lingering effects that can last for weeks or months. The factors related to concussion susceptibility and the subsequent recovery times are not well known or understood at this time. Several factors have been suggested and they include the individual&#8217;s concussion history, the severity of the initial injury, history of migraines, history of learning disabilities, history of psychiatric comorbidities, and possibly, genetic factors. Many studies have individually investigated certain factors both the short-term and long-term effects of concussions, recovery time course, susceptibility and recovery. What has not been clearly established is an effective multifaceted approach to concussion evaluation that would yield valuable information related to the etiology, functional changes, and recovery. The purpose of this manuscript is to show one such multifaceted approached which examines concussions using computerized neurocognitive testing, event related potentials, somatosensory perceptual responses, balance assessment, gait assessment and genetic testing.

There is great variability in an individual&#8217;s risk for concussion and their corresponding recovery. A multifaceted approach to concussion evaluation is warranted; including baseline testing of athletes before participation in sport and timely evaluation post injury. The goal of this protocol is to provide an appropriate multifaceted approach to examine concussions.

Concussions are occurring at alarming rates in the United States and have become a serious public health concern. The CDC estimates that 1.6 to 3.8 ...

Importance of Jumping Ability in Handball Throwing Speed and Accuracy

Throwing the ball to score a goal in handball is a critical action for success in offensive play. Speed and accuracy are two determining factors for successful throws. While there is substantial research on the importance of these factors, discrepancies exist regarding their relationship. This study aims to analyze the impact of jumping ability on throwing speed and accuracy across different competitive levels in handball. Thirty-five male handball players were recruited from amateur and professional levels. Jumping ability was assessed and throwing speed and accuracy were measured using a high-performance sports radar. Significant differences (p &lt; 0.05) were found between amateur and professional groups in countermovement jump (CMJ) and throwing speed jump. The comparative analysis revealed significant differences in throwing speed and in correct and incorrect throws, with large to very large effect sizes. Pearson's r correlation indicated significant correlations between throwing speed jump and CMJ, countermovement jump left (CMJL), and countermovement jump right (CMJR), and between throwing speed deficit and CMJL in the total sample. The results show that professional handball players exhibit higher throwing accuracy and speed compared to amateurs. Throwing speed and accuracy are positively correlated with performance in male handball players.

The study examined the influence of jumping ability on throwing speed and accuracy in 35 male handball players. Professional players demonstrated superior accuracy and speed compared to amateurs. Jumping ability was identified as a robust predictor of competitive level and exhibited a positive correlation with throwing performance.

Throwing the ball to score a goal in handball is a critical action for success in offensive play. Speed and accuracy are two determining factors for ...

Autonomic Function Following Concussion in Youth Athletes: An Exploration of Heart Rate Variability Using 24-hour Recording Methodology

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To date, return-to-activity decision-making has been anchored in the monitoring of self-reported concussion symptoms and neurocognitive testing. However, multi-modal assessments that corroborate objective physiological measures with traditional subjective symptom reporting are needed and can be valuable. Heart rate variability (HRV) is a non-invasive physiological indicator of the autonomic nervous system, capturing the reciprocal interplay between the sympathetic and parasympathetic nervous systems. There is a dearth of literature exploring the effect of concussion on HRV in youth athletes, and developmental differences preclude the application of adult findings to a pediatric population. Further, the current state of HRV methodology has primarily included short-term (5-15 min) recordings, by using resting state or short-term physical exertion testing to elucidate changes following concussion. The novelty in utilizing a 24 h&#160;recording methodology is that it has the potential to capture natural variation in autonomic function, directly related to the activities a youth athlete performs on a regular basis. Within a prospective, longitudinal research setting, this novel approach to quantifying autonomic function can provide important information regarding the recovery trajectory, alongside traditional self-report symptom measures. Our objectives regarding a 24 h recording methodology were to (1) evaluate the physiological effects of a concussion in youth athletes, and (2) describe the trajectory of physiological change, while considering the resolution of self-reported post-concussion symptoms. To achieve these objectives, non-invasive sensor technology was implemented. The raw beat-to-beat time intervals captured can be transformed to derive time domain and frequency domain measures, which reflect an individual&#39;s ability to adapt and be flexible to their ever-changing environment. By using non-invasive heart rate technology, autonomic function can be quantified outside of a traditional controlled research setting.

We demonstrate a 24 h heart rate recording methodology to evaluate the influence of concussion across the recovery trajectory in youth athletes, within an ecologically valid context.

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To ...

Development and Implementation of a Multi-Disciplinary Technology Enhanced Care Pathway for Youth and Adults with Concussion

The evidence-informed standardization of care along disease lines is recommended to improve outcomes and reduce healthcare costs. The aim of this project is to 1) describe the development and implementation of the Concussion Carepath, 2) demonstrate the process of integrating technology in the form of a mobile application to enable the carepath and guide clinical decision-making, and 3) present data on the utility of the C3 app in facilitating decision-making throughout the injury recovery process. A multi-disciplinary team of experts in concussion care was formed to develop an evidence-informed algorithm, outlining best practices for the clinical management of concussion along three phases of recovery &#8211; acute, subacute, and post-concussive. A custom mobile application, the Cleveland Clinic Concussion (C3) app was developed and validated to provide a platform for the systematic collection of objective, biomechanical outcomes and to provide guidance in clinical decision-making in the field and clinical environments. The Cleveland Clinic Concussion app included an electronic incident report, assessment modules to measure important aspects of cognitive and motor function, and a return to play module to systematically document the six phases of post-injury rehabilitation. The assessment modules served as qualifiers within the carepath algorithm, driving referral for specialty services as indicated. Overall, the carepath coupled with the C3 app functioned in unison to facilitate communication among the interdisciplinary team, prevent stagnant care, and drive patients to the right provider at the right time for efficient and effective clinical management.

A multidisciplinary carepath to standardize disparate concussion care was developed and implemented at the Cleveland Clinic. The Cleveland Clinic Concussion (C3) mobile application was used to enable the carepath through biomechanical outcomes characterizing cognitive and motor function. Patient outcomes improved while cost of care was reduced following implementation.

The evidence-informed standardization of care along disease lines is recommended to improve outcomes and reduce healthcare costs. The aim of this project ...

Non-invasive Assessments of Subjective and Objective Recovery Characteristics Following an Exhaustive Jump Protocol

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