Effects of Kinesio Taping on Tuck Jump Performance in Competitive Male Athletes.

This study aimed to measure the acute effects of kinesio taping at different stretches on tuck jump performance in active individuals. Seventy-five males (23.01±2.24 years, 178.35±8.12 cm, 72.47±6.58 kg) were randomly distributed into three groups: (1) kinesio taping without stretch, (2) kinesio taping with approximately 50% stretch, and (3) kinesio taping with approximately 75% stretch. The tuck jump performance of all participants was determined at baseline, immediately after applying kinesio taping, and 24 and 72 hours later. The participants' tuck jump performance did not improve immediately after the kinesio taping application, 24 hours, and 72 hours after the application. No significant differences were found between the kinesio taping groups at any time point (p>0.05). This study demonstrated no effects of kinesio taping on neuromuscular performance.

Student perceptions of low-tech active learning and mastery of introductory biomechanics concepts.

This study documented student perceptions of five low-tech active learning exercises, their epistemology of learning, and examined the association between these variables and mastery of biomechanics concepts. Students (N = 152) in four introductory biomechanics courses at two universities completed the Biomechanics Concept Inventory (BCI) at the beginning and the end of the course. An additional 10-question survey was used at the end of the course to determine student perceptions of the active learning exercises and their epistemology of learning. Student learning of biomechanical concepts improved over levels reported in previous studies of traditional lecture instruction, but not as much as seen in other studies of active learning pedagogy in biomechanics and physics. Student perceptions of active learning were positive, particularly in individual rather than group exercises. A minority (12-16%) of these students had negative perceptions of group-based active learning exercises. Student perception of epistemology of learning was primarily constructivist; however, there was no evidence of these perceptions had associations with learning biomechanical concepts. Biomechanics instructors planning to use low-tech active learning exercises should communicate their philosophy of learning, expectations for the course, and progressively implement individual-based and group-based active learning experiences early in the course.

Contributions of Lower-Body Strength Parameters to Critical Power and Anaerobic Work Capacity.

ABSTRACT: Byrd, MT, Wallace, BJ, Clasey, JL, and Bergstrom, HC. Contributions of lower-body strength parameters to critical power and anaerobic work capacity. J Strength Cond Res 35(1): 97-101, 2021-This study examined the contribution of lower-body strength and isokinetic peak torque measures to the prediction of critical power (CP) and anaerobic work capacity (AWC). Fourteen recreationally trained males (mean ± SD age: 22.4 ± 2.5 years; height: 177.9 ± 7.7 cm; body mass: 84.2 ± 12.4 kg) with anaerobic training experience participated in this study. The lower-body strength measures included 1 repetition max bilateral back squat (BSq), isokinetic peak torque at 30°·s-1 [PT30], and isokinetic peak torque at 240°·s-1 [PT240] of the dominant leg. The CP and AWC were determined from the 3-minute all-out CP cycle ergometer test (CP3MT), with the resistance set at 4.5% of the total body mass. The CP was defined as the mean power output over the final 30 seconds of the test, and the AWC was calculated using the equation, AWC = 150 seconds (P150 - CP), where P150 equals the mean power output for the first 150 seconds. Stepwise regression analyses indicated that only BSq contributed significantly to the prediction of AWC (AWC = 0.0527 [BSq] + 8.094 [standard error of estimate = 2.151 kJ; p = 0.012]), with a correlation of r2 = 0.423. None of the strength parameters significantly predicted CP. These findings indicated that BSq strength accounted for 42% of the variance in AWC, but lower-body strength was not related to CP. The current results indirectly support the unique metabolic characteristics of both CP and AWC in providing separate measures of an individual's aerobic and anaerobic capabilities, respectively.

The effect of course format on student learning in introductory biomechanics courses that utilise low-tech active learning exercises.

Low-tech active learning (AL) exercises in face-to-face (F2F) undergraduate biomechanics courses improve student learning vs. lecture alone. This study compared learning of biomechanics concepts with AL implemented in two course formats (hybrid: HB vs. F2F). Additional aims were to investigate if student perceptions of learning epistemology and learning factors were related to course format. Students (n = 110) in four introductory biomechanics courses (two F2F, two HB) completed the 24-question Biomechanics Concept Inventory (BCI) at the beginning and the end of the course to determine their learning of biomechanical concepts. An additional eight questions were given with the post-test to determine student perceptions of the AL exercises and their epistemology of learning. Learning in the HB format was equivalent to the F2F course format when both implement AL in these students. Student perceptions of AL were generally positive and learning scores consistent with previous research on AL in biomechanics. There were mixed results of the effect of course format with one significant difference of three ratings of the nature of learning biomechanics and one significant difference of four ratings of AL by students. These results should be replicated and potential interactions with student perceptions and characteristics explored.

Squat Muscle Activation Patterns with Hip Rotations in Subjects with Genu Varum Deformity.

The purpose of this study was to compare muscle activation during the squat with different hip rotations (neutral, 15, 30, and 45° of internal and external hip rotation) in subjects with and without Genu Varum deformity deformity. Surface electromyography were recorded from 32 men with (n=16) and without (n=16) Genu Varum deformity. In the Genu Varum deformity group, the squats with 30, 45 and 15° of internal rotations of the hip showed significantly greater gluteus medius activation as compared to other positions. Moreover, the tensor fascia lata activity increased with greater external rotation of the hip, and significantly more than hip internal rotations (p<0.05). For vastus medialis and vastus lateralis, both hip internal and external rotation showed a significantly greater activation compared to the neutral hip positions (p<0.05). There were significant differences in the gluteus medius:tensor fascia lata activity ratio (p=0.001) and the vastus medialis: vastus lateralis activity ratio (p=0.001) between the different hip positions in the Genu Varum deformity and healthy groups. These results demonstrate that muscle activation patterns varied significantly with the position of different hip rotation in both groups. Those with Genu Varum deformity may use this information to aid in an injury prevention strategy by choosing squat positioning that favorably alters muscle activation patterns.

The influence of hip rotations on muscle activity during unilateral weight-bearing exercises in individuals with and without genu varum: A cross-sectional study.

OBJECTIVES: Hip rotation can influence gluteus medius (Gmed) muscle activity in individuals with genu varum (GV). This study examined different hip rotation positions on muscle activity during unilateral weight-bearing exercises in individuals with and without GV. DESIGN: Cross-sectional. SETTING: Outpatient physical therapy center. PARTICIPANTS: Forty-six physically active males, divided between control (n = 23) and GV groups (n = 23). MAIN OUTCOME MEASURES: Surface electromyography measured Gmed and tensor fascia latae (TFL) activity during pelvic drop (PD) and wall press (WP) exercises with different hip rotations. RESULTS: In the control group, WP with external rotation produced greater Gmed/TFL activity compared to other rotation positions. No difference was found for Gmed/TFL with PD in controls. In the GV group, Gmed activity increased with internal rotation in PD and WP; TFL activity increased only with external rotation in WP. Internal hip rotation produced higher Gmed/TFL activity than other positions in the GV group during both exercises. Greater Gmed/TFL activity was observed in the control group than GV during PD with external rotation, and WP with neutral positioning and external rotation. CONCLUSIONS: WP with external rotation in controls, and PD and WP with internal hip rotation in subjects with GV, are effective exercises to optimize GMed/TFL activity.

Creating and testing a GCP game in an asynchronous course environment: The game and future plans.

INTRODUCTION: The National Institute of Health has mandated good clinical practice (GCP) training for all clinical research investigators and professionals. We developed a GCP game using the Kaizen-Education platform. The GCP Kaizen game was designed to help clinical research professionals immerse themselves into applying International Conference on Harmonization GCP (R2) guidelines in the clinical research setting through case-based questions. METHODS: Students were invited to participate in the GCP Kaizen game as part of their 100% online academic Masters during the Spring 2019 semester. The structure of the game consisted of 75 original multiple choice and 25 repeated questions stemming from fictitious vignettes that were distributed across 10 weeks. Each question presented a teachable rationale after the answers were submitted. At the end of the game, a satisfaction survey was issued to collect player satisfaction data on the game platform, content, experience as well as perceptions of GCP learning and future GCP concept application. RESULTS: There were 71 total players who participated and answered at least one question. Of those, 53 (75%) answered all 100 questions. The game had a high Cronbach's alpha, and item analyses provided information on question quality, thus assisting us in future quality edits before re-testing and wider dissemination. CONCLUSIONS: The GCP Kaizen game provides an alternative method for mandated GCP training using principles of gamification. It proved to be a reliable and an effective educational method with high player satisfaction.

Effects of Relative Drop Heights of Drop Jump Biomechanics in Male Volleyball Players.

Previous cross-sectional studies have reported that higher drop heights do not always result in improved performance, and may increase injury risk during drop jumps (DJ). The purpose of this study was to analyze the kinematics and kinetics during the DJ in order to determine the relative drop height that maximize performance without exposing the lower extremity joints to unnecessary loads. Twenty male Division I college volleyball players volunteered. Data were collected using 11 infrared cameras and two force platforms. Participants performed three maximal effort countermovement jumps (CMJ). Subsequently, 50, 75, 100, 125, and 150% CMJ height (CMJH) was used to scale their relative drop height for three DJ trials per height. There was a significant increase in the landing phase impulse when the drop height exceeded 100%CMJH (p<0.05). At 125% and 150%CMJH, the negative work of knee and ankle significantly increased. The incoming velocity, kinetic energy, landing depth, maximum ground reaction force, landing impulse and power absorption of knee and ankle all increased with drop height (p<0.05). DJ height and reactive strength index following the drop landing were not statistically different between any of the drop heights (p>0.05). 50% to 100%CMJH may be the appropriate individual relative drop height for the DJ.

Impact kinetics associated with four common bilateral plyometric exercises.

BACKGROUND: This study quantified the peak vertical ground reaction force (VGRF), impulse, and average and instantaneous loading rates developed during bilateral plyometric exercises. METHODS: Fourteen collegiate male athletes performed 4 different bilateral plyometric exercises within a single testing session. Depth jumps from thirty, 60 and 90 centimeter heights (DJ30, DJ60, and DJ90, respectively), and a 2 consecutive jump exercise (2CJ), were randomly performed. The subjects landed on and propelled themselves off two force platforms embedded into the floor. The stance phase of each plyometric movement was analyzed for vertical force characteristics. The dependent variables were normalized to body weight. One-way repeated-measures ANOVA revealed significant differences between exercises (P≤0.05). RESULTS: For VGRF, only the DJ60 and 2CJ exercises were not different from each other. The impulses between DJ60 and DJ90, and DJ30 and 2CJ, were not different. All exercises were different from each other in regards to average and instantaneous loading rate except for DJ30 vs. DJ60, and DJ90 vs. 2CJ. The DJ90 condition reported the highest peak VGRF by approaching five times body weight. The 2CJ condition had similar impulse and loading rates as the DJ90 condition. CONCLUSIONS: A proper progression and detailed program planning should be utilized when implementing plyometric exercises due to their different impact kinetics and how they might influence the body upon ground contact.

Muscular and Neural Contributions to Postactivation Potentiation.

Wallace, BJ, Shapiro, R, Wallace, KL, Abel, MG, and Symons, TB. Muscular and neural contributions to postactivation potentiation. J Strength Cond Res 33(3): 615-625, 2019-This study's purpose was to explain the relationship between muscle factors (twitch potentiation [TP]) and neural factors (reflex potentiation) contributing to total postactivation potentiation (PAP) that couples these. The tibial nerve of 15 participants were stimulated intermittently for 20 minutes at supramaximal (Mmax) and submaximal (Hmax) intensities on separate days under 2 conditions: (a) rest (Control) and (b) after a 10-second plantarflexion maximum voluntary isometric contraction (MVIC). Isometric twitch torque and rate of force development (RFD) as well as soleus and gastrocnemius electromyographic values were analyzed. Torque and RFD TP were significantly greater 10 and 30 seconds after MVIC vs. Control. Postactivation potentiation of torque and RFD at Hmax were highest at 3 and 4.5 minutes after MVIC, respectively, with RFD significantly elevated. Electromyographic values were not different between conditions. Twitch potentiation significantly contributed to PAP at the following time points: 20 seconds, Hmax peak, and 20 minutes after MVIC (torque: R = 0.54, 0.76, and 0.70; RFD: R = 0.46, 0.59, and 0.53). The soleus significantly contributed to PAP torque at 20 seconds and 20 minutes after MVIC, and to PAP RFD at 20 seconds, 4.5 minutes, and 20 minutes (torque: R = 0.26 and 0.34, p ≤ 0.05; RFD: R = 0.65, 0.52, and 0.41). The gastrocnemius did not significantly contribute to PAP. Both muscle and neural factors play a significant role in PAP, and neural factors may play a more prominent role in RFD potentiation than torque potentiation.

Examination of a Multi-ingredient Preworkout Supplement on Total Volume of Resistance Exercise and Subsequent Strength and Power Performance.

Bergstrom, HC, Byrd, MT, Wallace, BJ, and Clasey, JL. Examination of a multi-ingredient preworkout supplement on total volume of resistance exercise and subsequent strength and power performance. J Strength Cond Res 32(6): 1479-1490, 2018-This study examined the acute effects of a multi-ingredient preworkout supplement on (a) total-, lower-, and upper-body volume of resistance exercise and (b) the subsequent lower-body strength (isokinetic leg extension and flexion), lower-body power (vertical jump [VJ] height), upper-body power (bench throw velocity [BTv]), and cycle ergometry performance (critical power and anaerobic work capacity). Twelve men completed baseline strength and power measures before 2 experimental visits, supplement (SUP) and placebo (PL). The experimental visits involved a fatiguing cycling protocol 30 minutes after ingestion of the SUP or PL and 15 minutes before the beginning of the resistance exercise protocol, which consisted of 4 upper-body and 4 lower-body resistance exercises performed for 4 sets to failure at 75% 1 repetition maximum. The exercise volume for the total, lower, and upper body was assessed. The VJ height and BTv were measured immediately after the resistance exercise. Postexercise isokinetic leg extension and flexion strength was measured 15 minutes after the completion of a second cycling protocol. There was a 9% increase in the total-body volume of exercise and a 14% increase in lower-body volume of exercise for the SUP compared with the PL, with no effect on exercise volume for the upper body between the SUP and PL. The increased lower-body volume for the SUP did not result in greater lower-body strength and power performance decrements after exhaustive exercise, compared with the PL. These findings suggested the potential for the SUP to increase resistance exercise volume, primarily related to an increased lower-body volume of exercise.

Contributions of Body-Composition Characteristics to Critical Power and Anaerobic Work Capacity.

Critical power (CP) and anaerobic work capacity (AWC) from the CP test represent distinct parameters related to metabolic characteristics of the whole body and active muscle tissue, respectively. PURPOSE: To examine the contribution of whole-body composition characteristics and local lean mass to further elucidate the differences in metabolic characteristics between CP and AWC as they relate to whole body and local factors. METHODS: Fifteen anaerobically trained men were assessed for whole-body (% body fat and mineral-free lean mass [LBM]) and local mineral-free thigh lean mass (TLM) composition characteristics. CP and AWC were determined from the 3-min all-out CP test. Statistical analyses included Pearson product-moment correlations and stepwise multiple-regression analyses (P ≤ .05). RESULTS: Only LBM contributed significantly to the prediction of CP (CP = 2.3 [LBM] + 56.7 [r2 = .346, standard error of the estimate (SEE) = 31.4 W, P = .021]), and only TLM to AWC (AWC = 0.8 [TLM] + 3.7 [r2 = .479, SEE = 2.2 kJ, P = .004]). CONCLUSIONS: The aerobic component (CP) of the CP test was most closely related to LBM, and the anaerobic component (AWC) was more closely related to the TLM. These findings support the theory that CP and AWC are separate measures of whole-body metabolic capabilities and the energy stores in the activated local muscle groups, respectively. Thus, training programs to improve CP and AWC should be designed to include resistance-training exercises to increase whole-body LBM and local TLM.

Limbic brain structures and burnout-A systematic review.

More profound understanding of the relationship between the burnout and the limbic system function can provide better insight into brain structures associated with the burnout syndrome. The objective of this review is to explore all evidence of limbic brain structures associated with the burnout syndrome. In total, 13 studies were selected. Four of them applied the neuroimaging technology to investigate the sizes/volumes of the limbic brain structures of burnout patients. Six other studies were to investigate the hypothalamus-pituitary-adrenal (HPA) axis of burnout patients. Based on the results of the studies on the HPA-axis and neuroimaging of the limbic brain structures, one can see great impact of the chronic occupational stress on the limbic structures in terms of HPA dysregulation, a decrease of BDNF, impaired neurogenesis and limbic structures atrophy. It can be concluded that chronic stress inhibits the feedback control pathway in the HPA axis, causes the decrease of brain-derived neurotrophic factor (BDNF), then impaired neurogenesis and eventually neuron atrophy.

Optimum Drop Jump Height in Division III Athletes: Under 75% of Vertical Jump Height.

Our purpose was to evaluate the vertical ground reaction force, impulse, moments and powers of hip, knee and ankle joints, contact time, and jump height when performing a drop jump from different drop heights based on the percentage of a performer's maximum vertical jump height (MVJH). Fifteen male Division III athletes participated voluntarily. Eleven synchronized cameras and two force platforms were used to collect data. One-way repeated-measures analysis of variance tests were used to examine the differences between drop heights. The maximum hip, knee and ankle power absorption during 125%MVJH and 150%MVJH were greater than those during 75%MVJH. The impulse during landing at 100%MVJH, 125%MVJH and 150%MVJH were greater than 75%MVJH. The vertical ground reaction force during 150%MVJH was greater than 50%MVJH, 75%MVJH and 100%MVJH. Drop height below 75%MVJH had the most merits for increasing joint power output while having a lower impact force, impulse and joint power absorption. Drop height of 150%MVJH may not be desirable as a high-intensity stimulus due to the much greater impact force, increasing the risk of injury, without increasing jump height performance.

Other People's Money: The Role of Reciprocity and Social Uncertainty in Decisions for Others.

Many important decisions are taken not by the person who will ultimately gain or lose from the outcome, but on their behalf, by somebody else. We examined economic decision-making about risk and time in situations in which deciders chose for others who also chose for them. We propose that this unique setting, which has not been studied before, elicits perception of reciprocity that prompts a unique bias in preferences. We found that decision-makers are less patient (more discounting), and more risk averse for losses than gains, with other peoples' money, especially when their choices for others are more uncertain. Those results were derived by exploiting a computational modeling framework that has been shown to account for the underlying psychological and neural decision processes. We propose a novel theoretical mechanism-precautionary preferences under social uncertainty, which explains the findings. Implications for future research and alternative models are also discussed.

Soil Aggregate Dynamics and Plant Community Response after Biosolids Application in a Semiarid Grassland.

Biosolids may improve the ecological function of degraded semiarid grasslands, but an understanding of the plant community is essential. An experiment was established in 2001 to determine the effects of a single surface application of biosolids on soil aggregate stability and the composition of the plant community in a semiarid grassland in British Columbia, Canada. Four treatments were evaluated: (i) surface biosolids application at 20 (Bio-20) and (ii) 60 Mg ha (Bio-60), (iii) mineral fertilizer, and (iv) a control. All treatments were replicated in four blocks. Soil was sampled during the spring (May), summer (June-July), and fall (October) in 2005, 2006, and 2009; the plant community was assessed in 2009. The greatest increases in size of stable aggregates relative to the control were in the spring and summer, which coincided with a 1.6- to 2.1-fold increase in the spring concentration of N within stable aggregates when biosolids were applied at 20 and 60 Mg ha , respectively. Nitrogen concentrations from the Bio-60 treatment were not different from the control, but the Bio-20 treatment had 42% greater N than all other treatments during summer. Biosolids application in this ecosystem did not increase perennial forage grass species relative to the control, and when biosolids were applied at a rate of 60 Mg ha there was a 75% reduction in the perennial forage plant species. The application of biosolids to native grasslands in semiarid environments should be done cautiously, especially when winter annual plant species (e.g., cheatgrass [ L.]) are present before application.

Power Asymmetries and Punishment in a Prisoner's Dilemma with Variable Cooperative Investment.

In many two-player games, players that invest in punishment finish with lower payoffs than those who abstain from punishing. These results question the effectiveness of punishment at promoting cooperation, especially when retaliation is possible. It has been suggested that these findings may stem from the unrealistic assumption that all players are equal in terms of power. However, a previous empirical study which incorporated power asymmetries into an iterated prisoner's dilemma (IPD) game failed to show that power asymmetries stabilize cooperation when punishment is possible. Instead, players cooperated in response to their partner cooperating, and punishment did not yield any additional increase in tendency to cooperate. Nevertheless, this previous study only allowed an all-or-nothing-rather than a variable-cooperation investment. It is possible that power asymmetries increase the effectiveness of punishment from strong players only when players are able to vary their investment in cooperation. We tested this hypothesis using a modified IPD game which allowed players to vary their investment in cooperation in response to being punished. As in the previous study, punishment from strong players did not increase cooperation under any circumstances. Thus, in two-player games with symmetric strategy sets, punishment does not appear to increase cooperation.

See One, Be One, Teach One: Faculty Use of Their Personal Health Narratives in Teaching.

BACKGROUND AND OBJECTIVES: Despite extensive examination of physician self-disclosure to patients and colleagues, no studies have directly investigated if physician faculty disclose personal health information to trainees for clinical teaching purposes. This study examines the types of personal medical information (personal health narratives) family medicine faculty use during resident teaching encounters and the beliefs of family medicine faculty about such disclosure. METHODS: Due to the exploratory nature of this study, the authors relied upon the triangulation of qualitative research methods to verify the use of and purpose for sharing personal health narratives by family physician faculty during teaching encounters. Direct observation, depth interviews, an attitude survey, and focus groups were sequentially used to evoke their beliefs about the purpose, benefits, and risks of sharing personal health narratives with residents. RESULTS: Ninety-eight percent of survey respondents acknowledged using personal health narratives in teaching, and half reported doing so infrequently. A large majority considered the practice an effective teaching method, but respondents were divided on potential risks. Focus group participants believed that disclosing health information is a powerful teaching method that should be utilized purposefully. Participants identified a need for guidance on how to effectively incorporate personal health narratives during teaching. CONCLUSIONS: The use of personal health narratives in teaching is well accepted among the physician faculty in this study. Although participants endorsed the practice, none had been trained to integrate self-disclosure in teaching, and most had not consciously considered the limits and risks of sharing their health histories with residents. Further research is needed to determine the prevalence, range, and depth of faculty disclosure in teaching and to assess the impact on learners.

The effect of power asymmetries on cooperation and punishment in a prisoner's dilemma game.

Recent work has suggested that punishment is detrimental because punishment provokes retaliation, not cooperation, resulting in lower overall payoffs. These findings may stem from the unrealistic assumption that all players are equal: in reality individuals are expected to vary in the power with which they can punish defectors. Here, we allowed strong players to interact with weak players in an iterated prisoner's dilemma game with punishment. Defecting players were most likely to switch to cooperation if the partner cooperated: adding punishment yielded no additional benefit and, under some circumstances, increased the chance that the partner would both defect and retaliate against the punisher. Our findings show that, in a two-player game, cooperation begets cooperation and that punishment does not seem to yield any additional benefits. Further work should explore whether strong punishers might prevail in multi-player games.