International Journal of Kinesiology and Sports Science

Background of the study: The COVID-19 pandemic has deeply impacted people’s daily lives, while the influence on behaviors and mental health among college students at the early stage of this pandemic is rarely studied. Objective: This study examined the impact of the COVID-19 pandemic in the early stage on college students’ physical activity (PA), sedentary behavior, and depressive symptoms and its impact on sex and ethnic disparities in these outcomes. Methods: Using a cross-sectional design, 111 college students were recruited, and the data were collected before COVID-19 (n = 64) and in the early stage of the COVID-19 pandemic (n = 47), respectively. All participants completed a survey measuring depressive symptoms and wore an accelerometer to monitor PA behavior (light PA [LPA], moderate-to-vigorous PA [MVPA]), and sedentary behavior. Results: More MVPA engagement and lower levels of depressive symptoms were observed in the early-stage COVID-19 group compared to the before-COVID-19 group. The magnitude of the sex and ethnicity disparities in PA and depressive symptoms were reduced in the early-stage of the COVID-19 pandemic. Conclusion: Understanding college students’ behaviors and mental health in the midst of a global crisis can be useful to determine appropriate strategies to address health and wellness in the chance of the lockdown returning and to further promote this vulnerable population’s physical and mental wellness.

Background: The imposed stay-at-home restrictions with the coronavirus (COVID-19) pandemic disrupted daily routines and impacted some population groups more than others. One such group included university students who were forced to adapt to online classes reducing face to face interactions. The uncertainty associated with this change may have created a sense of anxiety and fear towards the virus. Objective: The objective of this study was to measure the level of fear associated with COVID-19 in Canadian undergrad university students and the influence fear may have on their health-related behaviours during an ongoing pandemic. Methods: Students enrolled in four large universities in the province of Alberta were invited to complete an online Fear of COVID-19 Scale (FCV-19S) from January 4th to February 15th, 2021. Results: Undergraduate students (n=680; 73.4% female) with a mean age of 23 (SD 5) years had an average FCV-19 score of 17.1 (SD 6.1) out of 35. Many students (60%) categorized their fear in the moderate range and females were more likely to have a higher FCV-19 score (p<.05) than males. Increases in alcohol and substance use, sleeping and eating behaviours were significantly associated (p<.05) with higher FCV-19 scores (p=.047; p=.000; p=.000). Most student’s smoking behaviour (80.5%) remained the same, however physical activity decreased. Conclusion: In summary, students showed a moderate level of fear associated with COVID-19 during the pandemic, and those with greater levels of fear reported more negative heath behaviour choices. These results highlight that continued restrictions during the COVID-19 pandemic continue to negatively impact student’s health behaviours.

Background: It is less known how the constraints placed upon public spaces and social interaction have impacted college students’ motivation to be physically active. Objective: This study examined, first, the changes in college students’ body mass index (BMI), physical activity (PA), and self-determined motivation before and during the COVID-19 third-wave lockdown and, second, the role of moderate-to-vigorous PA (MVPA) and self-determined motivation on BMI during the lockdown. Method: This study was a longitudinal prospective study with two data collection phases. A sample of 104 college students (69 females, 35 males, Mage = 18.19[1.5]) completing both pre- and posttest data turned in self-report data on BMI, PA (vigorous PA - VPA, moderate PA - MPA), MVPA, and self-determined motivation. Results: The results showed a statistically significant increase in participants’ BMI (t[79] = 4.70[2.98], p =.001, d =.11) but no statistically significant changes in PA. The findings demonstrated changes in college students’ integrated regulation (↓; t[78]= -3.20[.16], p =.002, d =.35), identified regulation (↓; t[76] = -4.07[.16], p .001, d =.52), extrinsic regulation (↑; t[78] = 2.28[1.80], p =.025, d =.02), and amotivation (↑; t[78] = 4.42[1.21], p .001, d =.48). Finally, neither PA nor self-determined motivation played a role in BMI, but the previous MVPA and BMI did. Conclusion: This study suggests that COVID-19 had a negative impact on self-determined motivation decreasing adaptive and increasing maladaptive motivation. However, neither MVPA nor self-determined motivation played a role in BMI during the COVID-19 lockdown. Instead, pre-COVID BMI (large effect) and MVPA (small effect) determined students’ BMI during the lockdown.

Introduction: Knowing which physiological variables predict running performance could help coaches to optimize training prescription to improve running performance. Objective: The present study investigated which physiological respiratory responses could predict 3000-m running performance. Methods: Seventeen amateur runners (29.82±7.1years; 173.12±9.0cm; 64.59±9.3kg) performed a maximal graded running test on a treadmill. The ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen consumption (VO2max) were assessed, as well as the respective velocities (vVT, vRCP, vVO2max). After 72 to 96 hours the runners performed the 3000-m running field test. The relationships between variables were performed using Pearson product momentum correlations. Thereafter, simple and multiple regression models were applied. The significance level adopted was 5% (p<0.05). Results: The majority of physiological responses were positive and well related to each other (r≥0.70; p<0.05). Despite vVT, vRCP, and vVO2max demonstrating a higher and inverse relationship with 3000-m time (r=-0.92; r =-0.96; r =-0.89; p<0.05), the multiple regression model indicated that vRCP and vVO2max are the best variables to predict 3000-m performance in experienced amateur road runners (R2=0.94). The equation proposed by the model was: 3000-m(s)=1399.21–[31.65*vRCP(km.h-1)]–[12.06*vVO2max (km.h-1)]. Conclusion: The vRCP and vVO2max may be used to predict 3000-m performance using only a maximal running test on a treadmill. In practical terms, coaches and physical conditioners can use performance in the 3000-m to select different exercise running intensities to prescribe exercise training intensities.

Background: Muscle energy technique (MET) is asn osteopathic treatment technique that is utilized frequently in the clinical setting, yet the overall effectiveness is minimally supported within literature. MET is an osteopathic technique that involves an isometric contract relax technique intended to improve alignment and enhance neuromuscular education. Objective: The purpose of this study was to determine the effectiveness of MET on running kinetics on subjects with low back pain. Method: A quasi-experimental research design was implemented and subjects, all of whom either had a history of or currently experience low back pain, underwent pre-intervention data collection of: anthropometric measurements, medical history, dorsaVi 3D running analysis, and a musculoskeletal and neurological clinical exam. Subjects underwent 6 weeks of isolated lumbo-pelvic MET at a frequency of twice a week, and were instructed to avoid all other treatment. Post-intervention data collected included a clinical exam and another dorsaVI running analysis. Results: Data was analyzed including: pre and post-treatment initial peak acceleration, ground contact time, and ground reaction force. A paired t-test comparing pre and post mean kinetic changes demonstrated the following p values: initial peak acceleration p = .80, ground contact time p = .96, and ground reaction force p = .68. Conclusion: This study demonstrated that isolated MET treatment is not statistically significant for changing 3D kinetic running variable in subjects with low back pain. Clinical Implications: Recommend healthcare providers to use a multi-treatment approach for low back pain. Future research should include a control group and larger sample size.

Background: Neuromuscular electrical stimulation (NMES) has been used clinically for many years as a modality to improve muscular strength and endurance. Recently, equipment manufacturers have developed over-the-counter NMES units to target specific muscle groups, particularly the abdominal region. Objective: To study the effects of self-administered neuromuscular electrical stimulation (NMES) on changes in abdominal muscle strength and endurance, core strength, abdominal girth, and subjective measures of body satisfaction and shape. Methods: Fifty-three adults were randomly assigned into high intensity (HI: n=27) or low intensity (LI: n=26) groups. The NMES device for the LI group had been altered so that subjects felt some tactile sensation, but the intensity was not sufficient to elicit a muscular contraction. All subjects stimulated their abdominal muscles 5 days per week (30 minutes per session) for 6 weeks. Subjects were tested at Baseline, 2, 4, and 6 weeks. Results: The HI group had a significantly greater increase in strength at 4 weeks (19%) and 6 weeks (29%) compared to the LI group and performed significantly more curl-ups than the LI group at 2 weeks (62%). Both groups had a significant increase in core strength over the course of the study, with no difference between groups. There was no change in abdominal girth between groups. Both groups had significant improvements in body satisfaction from Baseline to 4 weeks and Baseline to 6 weeks, with no significant interaction. Conclusions: Results of the current study indicate that high intensity NMES can significantly increase abdominal strength and endurance compared to LI intensity (control) stimulation. Results for subjective measures tended to favor the HI group, but were less conclusive, since the LI group also had some positive changes.

Background: Abdominal adiposity is associated with high risk of cardiometabolic diseases. Waist circumference has been used as a surrogate measure of abdominal adipose tissue in both youth and adults. Objectives: The present study evaluated whether cardiorespiratory fitness and leg power (LP) were independently associated with abdominal adipose tissue in 12-16-year-old Nigerian adolescents. Methods: This cross-sectional study comprised 2047 (1087 girls and 960 boys) adolescents who were evaluated for cardiorespiratory fitness and leg power. The cardiorespiratory fitness and leg power were assessed using the progressive cardiovascular endurance run (PACER) test and the vertical jump (VJ) test, respectively. Abdominal adiposity was evaluated with the waist circumference (WC). Regression models controlling for age and maturity status were used to assess the association of fitness and LP with WC. Results: Low leg power had significant negative association with the risk of abdominal adiposity in both girls (β=-0.307; p0.001) and boys (β=-0.262; p0.001). The observed relationship was independent of fitness, whereas the relationship between fitness and risk of abdominal adiposity was partly determined by leg power. Conclusion: Leg power and fitness were independently associated with the risk of abdominal adiposity in adolescents, but the association of leg power was stronger in girls. Health promotion efforts targeting reduction of abdominal adipose tissue should also include muscular power training type activities in addition to endurance-related activities.

Background: Regression equations using anthropometric measurements to predict soft (fat mass [FM], lean mass [LM], wobbling mass [WM]) and rigid (bone mineral content [BMC]) tissue masses of the extremities and core body segments have been developed for younger adults (16-35 years), but not older adults (36-65 years). Tissue mass estimates such as these would facilitate biomechanical modeling and analyses of older adults following fall or collision-related impacts that might occur during sport and recreational activities. Purpose: The purpose of this study was to expand on the previously established tissue mass prediction equations of the head, neck, trunk, and pelvis for healthy, younger adults by generating a comparable set of equations for an older adult population. Methods: A generation sample (38 males, 38 females) was used to create head, neck, trunk, and pelvis tissue mass prediction equations via multiple linear stepwise regression. A validation sample (13 males, 12 females) was used to assess equation accuracy; actual tissue masses were acquired from manually segmented full body Dual-Energy X-ray Absorptiometry scans. Results: Adjusted R2 values for the prediction equations ranged from 0.326 to 0.949, where BMC equations showed the lowest explained variances overall. Mean relative errors between actual and predicted masses ranged from –2.6% to 6.1% for trunk LM and FM, respectively. All actual tissue masses except head BMC (R2 = 0.092) were significantly correlated to those predicted from the equations (R2 = 0.403 to 0.963). Conclusion: This research provides a simple and effective method for predicting head, neck, trunk, and pelvis tissue masses in older adults that can be incorporated into biomechanical models for analyzing sport and recreational activities. Future work with this population should aim to improve core segment BMC predictions and develop equations for the extremities.

Background: In athletes with anterior cruciate ligament (ACL) deficiencies could assess functional capabilities with different instruments such as use of a camera in vivo situation. However, these methods have suffered from a large number of limitations such as inability to be repeatable and complexity in technique. Objective: The main purpose of this study was to compare gait pattern of the athletes with ACL injury and able-bodied subjects using an accelerometer. Method: A three-dimensional accelerometer was placed over the tibia tuberosity of 20 healthy and 20 individuals with ACL-deficiencies (ACLD). After walking on the treadmill, the principal components of the acceleration data were calculated using MATLAB software. Results: In this study, Principle Component analysis was used for statistical analysis. The results indicated that subjects with ACL deficiency have different gait pattern compared to the control group. The major differences between stride trajectories of the two groups were at the end of mid-swing and the beginning of terminal swing phases in vertical axis. ACL deficient subjects exhibited different gait patterns during mid and terminal stance phases in anterior- posterior axis compared with normal controls. Conclusions: The difference in gait between subjects with ACL deficiency and healthy subjects are depends on variation in the amount of knee flexion and tibia rotation that could be altered to motor recruitment.

Background: A common research question in far-target aiming has been the importance and significance of the final visual fixation before movement initiation. In rolling tasks, such as 10-pin bowling, location of point of aim needs not be at the final target, the pins, but may be located at any point along the trajectory of the ball. Objective: Specific interest in the present experiment has focused on the relationship between visual point of aim and performance accuracy, and the relationship of visual control strategies utilized by expert performers. Methods: Skilled bowlers (N=7) performed 20 trials per condition concentrating on visual targets in different distances along the bowling lane (20, 40, 60 feet, and self-selected). Ball trajectory was tracked using a video based system and eye movement was measured using an eye tracking system. Results: Deviation of the ball from the visual target increased with visual target distance, while deviation of the ball from the pins was the lowest in the self-selected visual targets, followed by aiming at the pins. The final fixation duration before movement initiation was not associated with ball accuracy regardless of visual target locations. However, results demonstrated the association between final fixation duration task difficulty, that is, longer final fixation duration with increased visual target distance. Conclusion: The results indicate that visual fixations before movement initiation are uncharacteristically long while visual fixations just before the completion of the movement are relatively short.

Background: Anterior cruciate ligament (ACL) injuries are some of the most common knee injuries that occur in the US, accounting for around 200,000 documented cases per year. Varying levels of severity can determine whether surgery is required or if physical therapy will suffice. One of the most common complications for patients is that there is significant atrophy of the impacted limb. Yet, there has not been definitive proof explaining this mechanism. Objective: The primary goal for this review was to examine some of the biochemical differences that tend to occur within and surrounding an ACL injury and the mechanisms involved in skeletal muscle atrophy and regenerative capabilities. Outcome: Multiple studies have found a connection between time spent inactive from the injury and the percentage of retained muscle after exercising again. Among decreases in muscle mass and muscle volume changes, analyses have also revealed alterations in alpha-2 macroglobulin, myostatin, heat shock protein-72, mechano GF-C24E, synovial fluid, and histochemical alterations in collagen and cartilaginous states which all seem to be primary factors in regulating effectiveness and speed of recovery from ACL injury. Conclusion: the influx of various cytokines as a response to the initial injury in relation to inflammation change the chemical and physical environment of the knee, making recovery significantly more difficult and time-consuming. Timing of injury, surgery, and re-initiation of movement after surgery are very important factors that can minimize overall damage and reduce recovery time.

Background: A 19-year-old man presented with right knee pain while bearing weight on the right leg and difficulty bending the right knee. He was diagnosed with a complete -tear of the anterior cruciate ligament. After ACL reconstruction this individual was referred to physical therapy treatment. Objective: To investigate if neuroscience pain education, and eccentric training, have any therapeutic significance in post-ACL reconstructive patients. Method: After assessment, the first day of the first week, introduced a treatment protocol consisting of basic range of motion (ROM) and isometric exercises for three sets of 10–30 sec hold. From first to fourth week eccentric exercises along with pain neuroscience education (PNE) sessions were given on alternate days, with three sessions for PNE and eccentric exercises until fourth week. Result: As shown in this study, treatment with a combination of PNE and eccentric training results in improved quadriceps muscle strength, range of motion, and overall function. Conclusion: This report suggested that PNE in conjunction with eccentric exercise has clinical merit. Clinical implication of study is examining the effectiveness of this approach should be conducted in the form of well-designed, clinical studies.

Background: Due to individual patterns of body and clubhead movement in golf, a uniform assessment method has been considered difficult. Objective: This study aimed to establish a statistical model that can assess a player’s shot performance in a short time by analyzing the relationship between the golf strokes and their clubhead movement data. Methods: In this cross-sectional, observational study, we analyzed the clubhead movement data of 15 driver shots (three sets of five shots) by 14 amateur golfers (AGs) and 14 skilled golfers (SGs). After performing warm-up, participants used their own drivers to hit at a crosshair-shaped target positioned in an indoor driving range. Data were captured for each parameter relating to clubhead movement at the moment of impact using the Doppler radar launch monitor (FlightScope X3). Results: Face-to-target angles showed significant interactions between three conditions (Set 1, Set 2, and Set 3) and two groups (AGs and SGs); SGs consistently displayed smaller angles in every set than their amateur counterparts (p0.5). A post-hoc test further increased the discrepancy between Sets 2 and 3 for AGs and SGs. In addition, a strong correlation was found between each participant’s average number of strokes and the mean clubhead speed (CHS) across 15 driver shots. A stepwise multiple regression analysis indicated that CHS was a significant predictor of a player’s average number of strokes. Conclusion: SGs achieved extremely accurate clubface control during multiple hits with a high CHS. We found no trade-off relationship between a higher CHS and smaller face-to-target opening/closing in SGs.

Purpose: The purpose of this study was to examine maximal jaw opening as a strategy to elicit concurrent activation potentiation during countermovement vertical jump performance and bilateral grip strength assessment in both males and females. Methods: Twenty-four males (age 21.25 ± 1.45 years; height 177.64 ± 7.67 cm; mass 83.87 ± 9.08 kg) and 24 females (age 21.38 ± 2.12 years; height 165.84 ± 8.96 cm; mass 66.4 ± 13.42 kg) participated in this investigation. Maximal countermovement jump height was recorded using a Just Jump Mat, and dominant and non-dominant handgrip strength was recorded using a digital hand dynamometer under two experimental conditions: jaw relaxed and jaw maximally opened. Paired-sample t-tests were conducted for each dependent variable of interest to determine the differences between the research conditions. Results: Maximally opening the jaw led to improvements in vertical jump height (p = 0.013, d = 0.225), dominant hand (p = 0.028, d = 0.162), and non-dominant handgrip strength (p = 0.011, d = 0.241) in males, and although these variables were improved in females under the jaw open condition, that improvement did not reach statistical significance (p > 0.05). Conclusion: This study supports maximally opening the jaw as an effective strategy for producing concurrent activation potentiation, particularly in males.

Background: Baseball pitching is a dynamic movement where the lower extremities generate and sequentially transfer energy to the upper extremities to maximize ball velocity. The need for lower body muscular strength to produce adequate push-off and landing forces has been documented; however, the influence footwear and surface inclination has on muscle activation remains unknown. Objectives: Determine how pitching in molded cleats and turf shoes from a pitching mound and flat ground affects stride-leg muscle activation in youth baseball pitchers while determining percent activation during each pitching phase. Methods: Cross – sectional study analyzing mean muscle activity and percent activation of the vastus medialis, semitendinosus, tibialis anterior, and medial gastrocnemius on the stride-leg of 11 youth baseball pitchers when pitching fastballs. Results: Footwear did not significantly alter vastus medialis or semitendinosus muscle activation (P 0.05). The turf shoe x pitching mound interaction elicited significantly (P 0.05) greater mean muscle activity in the medial gastrocnemius and tibialis anterior from stride foot contact to maximum glenohumeral internal rotation. Molded cleats produced greater activation levels in the tibialis anterior on flat ground from stride foot contact (0.374 ± 0.176 mV) to ball release (0.469 ± 0.150 mV). Conclusion: Findings suggest footwear significantly alters the activity level of the ankle stabilizing musculature. Youth baseball pitchers and coaches should be cognizant of what footwear is worn on a pitching surface. Maximal activation of the tibialis anterior and medial gastrocnemius can ensure the stride leg is adequately stabilized to absorb the momentum generated by trail leg.

Background: Playing the drum kit is a physically and cognitively demanding task, and skilled drummers share many such attributes with elite athletes. The ‘double pulse’ muscle activation (DPMA) pattern is a motor control strategy that has been observed in athletes of sports involving ballistic movements (e.g., baseball, golf, Mixed Martial Arts), and is believed to function to increase force transfer to the target. Objective: This study examined the muscle activation patterns of highly skilled drummers for evidence of a DPMA during high-velocity cymbal crashes. Methods: Five drummers were instrumented with electromyography electrodes on the right latissimus dorsi, triceps brachii, erector spinae, rectus abdominis, deltoideus posterior (DP), teres major, extensor carpi radialis, and flexor carpi ulnaris muscles. Six trials of data were collected, including a resting baseline, three maximum voluntary exertions (MVE) consisting of maximal effort cymbal crashes, a drumming pattern that included multiple crashes, and a ‘free-play’ trial. Results: The DPMA waveform was observed in all trials, but only those observed during the MVE trials were confirmed to coincide with the crashing movement via video analysis. The DP muscle – which functions to extend the shoulder joint to crash the stick on to the cymbal – exhibited confirmed DPMAs the most frequently. Conclusion: The extent to which drummers use the DPMA to produce high-velocity cymbal crashes within authentic playing conditions is inconclusive and needs further examination. Future study of the DPMA phenomenon in drummers would benefit from the addition of 3-dimensional motion capture to further understand the purpose of the muscle contractions of the DPMA.

Background: Fitness equipment manufacturers have developed non-motorized treadmills (NMT) to better replicate overground running, a characteristic which motorized treadmills (MT) purportedly lack. Because NMTs are novel, limited empirical evidence exists regarding acute physiological and neuromuscular activity responses to its use. Objectives: The purpose of this investigation was to examine the effect of walking and running on an NMT and MT on exercise economy (EE), cardiometabolic responses, lower-body muscle activity, and rating of perceived exertion (RPE) in division II female cross-country athletes. Methods: Thirteen female cross-country athletes volunteered to complete a treadmill protocol that consisted of a warm-up walk, a 5-min walk, a 5-min run, and a 5-min cool-down walk on an NMT and MT on two separate occasions. During both treadmill conditions, VO2, RER, neuromuscular activity, HR, and RPE were recorded and analyzed every minute. Results: VO2 (NMT= 36.8 ± 10.0 ml/kg/min; MT= 27.4 ± 6.7 ml/kg/min), RER (NMT= 1.02 ± 0.14; MT= 0.89 ± 0.08), HR (NMT= 167 ± 18 bpm; MT= 142 ± 21 bpm), and RPE (NMT= 12 ± 2; MT= 9 ± 2) measures were significantly (p<0.05 for all) greater on the NMT than the MT in walking and running. Conclusions: The greater VO2, RER, and HR experienced on the NMT indicates higher physical exertion, and the greater RPE on the NMT indicates the participants’ perception of exertion correspond to the physiological responses. While cardiometabolic demand was greater on the NMT, thereby suggesting exercise economy was greater with the MT.

Background: Aerobic exercise has been shown to impart anti-inflammatory effects partly through increased secretion of interleukin-6 (IL-6). Still unclear, however, is whether resistance exercise (RE) also enhances IL-6 secretion. Objective: The present study aimed to examine the effect of RE, performed at varying volume loads (VL), on plasma IL-6. Methods: Ten subjects (seven males and three females: age 37.9 ± 11.4 years; height 170.81 ± 11.16 cm; weight 71.36 ± 11.26 Kg.) participated in three randomized RE protocols: high VL (HVL) (5 sets x 20 repetitions at 45% 1-repetition maximum (1-RM), medium VL (MVL) (3x12 at 75% 1-RM), and low VL (LVL) (2x4 at 90% 1-RM) each separated by 96 hours. Capillary blood for IL-6 measurements was drawn immediately pre-exercise, immediately post-exercise, and 1- and 2-hours post-exercise. Results: There were no significant differences in plasma IL-6 between exercise condition (LVL, MVL, HVL) or at any time point (p=0.422 and p=0.870, respectively). Conclusion: Plasma IL-6 levels are not acutely sensitive to RE, regardless of volume load; therefore, any reported anti-inflammatory effect of RE appears to operate outside of the exercise-induced IL-6 pathway.

Background: It is well established that regular participation in exercise and virtual reality (VR) environments are important tools for improving or maintaining human health and cognitive function. Objectives: This study examined the effects of acute exercise and VR environments on children’s memory function and exercise preference (i.e. cycling with or without the use of VR technology). Methods: Α 2×3 factorial design was adopted with two measures (pre, post) and three study groups. Forty-five healthy children aged 9 to 13 years (Mage = 10.91±1.24 years) voluntarily participated in the study. Participants were randomly assigned into three groups receiving different treatment: (1) an exercise+VR group that cycled for 15 min in a VR environment (forest path) combined with basic mathematical problem-solving tasks, (2) an exercise group that cycled for 15 min, and (3) a no-exercise group that sat in a specific place in a lab for 15 min (the control group). Before and after the acute exercise, all the groups completed the Sternberg Memory Task. Upon completion of the intervention, the two exercise groups completed measures of enjoyment, intention and attitudes towards cycling. The exercise+VR group also completed a scale capturing the VR’s usability. Results: The results show that the exercise group scored higher on Sternberg’s Memory Task (p .05) after the acute exercise treatment (post) than before it (pre). Similarly, the exercise+VR participants scored higher on the post-intervention memory task than did the exercise and control groups (p .05). Moreover, the exercise+VR group reported higher scores on enjoyment, intention and attitude towards cycling than the exercise group, but this difference was not statistically significant (p .05). Finally, the exercise+VR participants recorded high scores on the usability of the VR system during the acute exercise programme. Conclusions: These findings are in line with those of previous studies, underlining the important roles of exercise and VR environments on youths’ cognitive function.

Jumping and balance are necessary skills for most athletes, and mini-trampoline training has been shown to improve them. Little is known about the acute effect of mini-trampoline jumping on jump performance and dynamic balance. Objectives: The purpose of this study is to investigate the effect of 6 maximal jumps on a mini-trampoline on countermovement vertical jump (CMVJ) variables and on balance parameters. Methods: Twenty one recreationally trained individuals participated in three testing sessions and were either allocated to a control group (N=10) or a trampoline group (N=11). All the participants performed a dynamic warm up prior to their assessments. Baseline CMVJ and balance assessments were measured. For the jump performance tests, the control group rested for 30s, and the trampoline group performed 6 maximal CMVJs on a mini-trampoline. Immediately following the trampoline jumps or the rest period, participants performed three jump trials. The jumping protocol was repeated every minute up to 5 minutes and balance was reassessed immediately after only. Results: There was no significant interaction of time by group and no group effects in all the jumping parameters, however, there was a significant increase in jump height (p <0.001) post-condition, and a significant decrease in peak power (p= 0.01) at the 4th minute for both groups. There was no significant interaction of time by condition, no time effect and no group effect (p>0.05) on the balance variables. Conclusion: These results do not support our hypothesis and show that trampoline jumping does not improve jump and balance performance acutely.

Background: Obesity is a major public health issue in the United States (U.S.), affecting an estimated 78 million US adults. Aerobic exercise (AE) is recommended by the American College of Sports Medicine to prevent and treat obesity, yet the effects of AE on circulating hunger hormones including acylated ghrelin and its biological catalyst, ghrelin o-acyltransferase (GOAT) are less known. Objectives: We investigated the effects of AE on circulating concentrations of appetite regulating hormones and GOAT in a pilot sample of adults classified with normal weight (NW) and obese (OB) body weight status. Methods: Using a quasi-experimental design, nine adults with NW (n=4, body mass index [BMI] = 21.3±1.2 kg/m2) and OB (n=5, BMI = 38.9±6.2 kg/m2) body weight status completed a preliminary health/fitness assessment. Participants returned to the laboratory on three separate occasions, separated by ≥ 48 hours to perform cycle exercise at 30% and 60% oxygen uptake reserve (VO2R) or a seated control session with no exercise for 40 min. Fifteen mL of blood was taken pre-and-post exercise and control and were assayed in duplicate. Nonparametric procedures determined whether mean rank differences existed between NW and OB for acylated ghrelin, leptin, insulin, and GOAT in response to exercise and control. Alpha levels were set a priori to p 0.05. Results: Significant mean rank reductions were found in GOAT after compared to before AE and control for NW and OB (p.05). Significant mean rank differences were found in acylated ghrelin after compared to before performing AE at 60% VO2R in NW and OB (p.05); however, differences were not observed between NW and OB (p.05). Conclusions: Our findings reveal the first available data regarding the effects of AE on GOAT, with NW and OB experiencing equivocal changes pre-to-post AE at 60% VO2R, and in response to a seated control session.

Background of study: Given the importance of movement and low exercise adherence among young adults, it is imperative to understand reasons for the love of movement. Objective: The purpose of this phronetic, qualitative study was to examine if the values of aerial practice encompassed elements of embodiment, techne (art), and phronesis (practical wisdom). Method: Participants were 13 undergraduate college students in an aerial practice class. Individual-based interview topics included exercise behavior and the values and meaning of aerial practice. Results: All participants were active regardless of aerial practice classification (e.g., beginners vs advanced). Beyond aerial practice, other exercises included dancing, yoga and aerial yoga, Pilates, aerobic activities (e.g., running and spinning classes), rock climbing and hiking, weight lifting, somatics and acrobatics. Based on the first theme, the love of aerial practice, techne aspects reflected fitness, skill improvement; challenging, infinite learning and determination. Art, performativity, fluidity included techne and embodiment, while the sensation of whole-body movement encompassed an embodied element for the love of aerial silks. A combination of phronetic and embodied elements were sense of community and inclusivity; novelty; it fits me. Embodied qualities of the second theme, challenges with aerial practice, included fear, injuries, bruises, pain. Fitness, skill, performance and the struggle to learn new movements linked to techne and the integral parts of movement. Phronetic categories regarding situation-specific reflections were time on the silk and unhealthy competition in the business world (territorial traits and lack of sharing). The third theme was future exercise plans and its categories included phronetic (decision-related) elements: practice and/or teach aerial silks; keep exercising. Conclusion: Artistic, embodied, and phronetic approaches in movement education can enhance the value and pursuit of movement.

Background: Various sprint interval training (SIT) programs have been used with athletes from a wide range of sports to evaluate its effects on physiological and performance adaptations. However, information regarding the effect of a short period of SIT on physiological adaptations of trained female futsal players is limited. Objective: This study evaluated the influence of sport specific SIT on anaerobic power and aerobic power in trained female futsal players. Method: Several aspects of V̇O2max and Wingate-based power were measured after SIT program performed for 4 weeks. Following pre-test, 16 trained female futsal players (V̇O2max = 41.21 ± 3.35 ml.kg-1.min-1) were randomized to either an intense exercise training consisting of sets of 5×40 meter maximum sprint efforts interspersed by a 10-second rest between sprints (3,4,5,6 sets/session from 1st to 4th week respectively with 3 minutes of recovery between sets), performed two sessions a week over 4 weeks (n=8) or a usual training control group (n=8). Results: Significant (except as shown) improvements (p < 0.05) after SIT were seen in: V̇O2max (5.8%), vV̇O2max (6%), V̇O2/HR (6.5%), peak power output (PPO) (7.6%), and mean power output (MPO) (14.9%), but no significant change was found in Heart rate at V̇O2max. Also, no significant enhancement in mentioned variables was found in the CON group. Conclusion: Present results indicate 4 weeks of sprint interval training program with low volume is associated with improvements in V̇O2max, vV̇O2max, V̇O2/HR, PPO, and MPO in trained female futsal players.

Background: Background: The direction of coaching is emphasized as a factor affecting the physical conditions of pencak silat martial arts athletes in all categories. One of the physical exercises that affects body composition is aerobic activity. Objective: This study aimed to examine the effects of aerobic interval (AI) training performed for five weeks on the body mass index (BMI), basal heart rate, and the VO2max of elite athletes. Methods: The study used an experimental design involving total sampling. Thirty national-level pencak silat elite athletes (17 men and 13 women) were involved in this study. Of the participants, 23 had a normal BMI of 18.5 – 24.9 kg/m2, and 7 had a BMI above 25 kg/m2 (overweight). Their average age was 23.67 + 4.10 years with an average height of 166.03 + 7.15) cm and average initial weight of 64.84 + 12.65 kg. They were in the preparation phase of their training. This experimental research used a one-group pre-test and post-test design. The Mi Xiaomi Body Scale 2 was used for bioimpedance analysis (BIA), and body composition (body weight, BMI, body fat percentage, bone mass, protein percentage, total water body percentage, visceral fat, body age, muscle mass, and basal metabolic rate [BMR]) and VO2max measurements were acquired using a multistage fitness test (MFT). The athletes lived in a dormitory where the food, type of training and exercise, and sleeping time were controlled to the exact condition. The AI training lasted 67–77 minutes per session, twice a week for five weeks, with vigorous intensity at 80–85% of the maximal heart rate, 5 minutes per interval, and 1 minute of rest between each interval. Results: The weight, BMI, body fat percentage, basal heart rate, and VO2max showed significant differences (p 0.05) after five weeks of AI training. However, AI training did not significantly alter muscle mass, percentage of water, percentage of protein, bone mineral density, or biological age. Conclusion: AI training performed for five weeks improved VO2max and decreased basal heart rate, body weight, and fat percentage.

Background: Blood lactate (La-) is commonly assessed in tests of sport performance. Sports that utilize intermittent high intensity effort, monitoring of La- from previous exercise can be useful to document intensity of effort. Objective: The purpose of this study was to investigate the role La- played during successive Wingate (Win) tests and subsequent anaerobic exercise performance. Method: Well-trained, national team athletes from Jordan (n = 31) volunteered to participate. A quasi-experimental design was utilized to test Win performance and La- concentration. All participants engage in two Win tests with one minute rest between sets. La- was collected at four time points (prior to Win test 1, immediately after Win 1, after Win 2 and after a 10 minute recovery period). Results: Findings from a multiple linear regression model (p = 0.032) showed increased levels of La- accumulation as a predictor to higher power and strength (p = 0.046). Conversely, peak aerobic capacity was a predictor for decreasing La- accumulation over time (p = 0.039), which may suggest faster recovery. Conclusion: Anaerobic athletes who participate in short, high intense bouts of exercise may require high intensity training programs to increase aerobic fitness, power output, and optimal performance. Practical applications include optimizing training programs to reflect competition.

Background: Despite the known benefits of physical activity (PA), most of the population in the United States fails to meet minimum recommended levels, and this lack of activity is believed to affect their health and well-being. Objective: The purpose of this study was to compare lifestyle behaviors of exercise and sleep in low, moderate, and high performers for maximal aerobic capacity (VO2max) and hand-grip strength (GS). Methods: Participants (n = 107, 19-62 years old) performed physical fitness assessments: estimated VO2max through submaximal cycle ergometry, and GS. Physical activity (PA) and sleep were assessed via self-reported questionnaires: physical activity as a vital sign (PAVS) and the Pittsburgh Sleep Quality Index (PSQI). Participants were categorized according to age and gender-specific normative values as low, medium, and high performer (LP, MP, and HP). Group characteristics were compared for each ranked variable using Kruskall-Wallis tests. Results: PAVS scores revealed 66.3% (n=68) of participants met minimum PA of 150 min/week (221.6 ± 177.8). According to VO2max performance groups, the LP group was taller, heavier, had higher diastolic blood pressure, and had a larger waist circumference than MP or HP (p =.000-.029), with moderate and high effect sizes. When categorized by relative GS, the LP group was heavier and had larger waist and hip circumferences than the HP group (p =.003-.011), all with high effect sizes. Conclusion: Despite high levels of self-report PA in this cohort, this did not translate to better cardiorespiratory fitness or muscular strength. Participants met PA guidelines but achieved suboptimal scores for VO2max and GS signifying elevated risk of mortality. The incongruity between PA levels and fitness classification suggest that lifestyle habits may not be a suitable surrogate for objective measurement of fitness.

Introduction: When comparing oral breathing versus nasal breathing, a greater volume of air can be transported through the oral passageway but nasal breathing may also have benefits at submaximal exercise intensities. Purpose: The purpose of this study was to determine breathing efficiency during increasing levels of submaximal aerobic exercise. Methods: Nineteen individuals (males N=9, females N=10) completed a test for maximal oxygen consumption (VO2max) and on separate days 4-min treadmill runs at increasing submaximal intensities (50%, 65%, and 80% of VO2max) under conditions of oral breathing or nasal breathing. Respiratory (respiration rate [RR], pulmonary ventilation [VE]), metabolic (oxygen consumption [VO2], carbon dioxide production [VCO2]) and efficiency measures (ventilatory equivalents for oxygen [Veq×O2-1] and carbon dioxide [Veq×CO2-1] were obtained. Data were analyzed utilizing a 2 (sex) x 2 (condition) x3 (intensity) repeated measures ANOVA with significance accepted at p≤0.05. Results: Significant interactions existed between breathing mode and intensity such that oral breathing resulted in greater RR, VE, VO2, and VCO2 at all three submaximal intensities (p<.05). Veq×O2-1 and Veq×CO2-1 presented findings that nasal breathing was more efficient than oral breathing during the 65% and 80% VO2max intensities (p<0.05). Conclusion: Based on this analysis, oral breathing provides greater respiratory and metabolic volumes during moderate and moderate-to-high submaximal exercise intensities, but may not translate to greater respiratory efficiency. However when all variables are considered together, it is likely that oral breathing represents the more efficient mode, particularly at higher exercise intensities.Keywords: Respiratory physiological processes, Musculoskeletal physiological phenomena, Running

Background: Motor skill is important to young children’s overall well-being. However, there has been a paucity of work examining the demographic characteristics on young children’ motor skill. Objective: The purpose of this study was to examine the differences in motor skills across socio-economic status (SES) and grade levels in elementary school children. Method: Participants were 651 kindergarten to 2nd grade children (mean age = 6.2 ± 0.9 years; 305 girls, 346 boys) recruited from two low SES schools and another two high SES schools. Selected motor skill items were measured using the Test for Gross Motor Development-3rd Edition (TGMD-3) instrument. Data were collected once at each school during physical education class and recess period. A 4 × 3 × 2 × 2 Multivariate Analysis of Variance (MANOVA) test was employed to examine the differences among grade, SES, ethnicity, and sex on TGMD-3 scores. Results: There were significant main effects for grade (Wilks’ lambda = 0.34, F (2, 1274) = 229.6, p < 0.001) and SES (Wilks’ lambda = 0.70, F (2, 637) = 136.3, p < 0.001). Follow-up tests revealed statistically significant differences between grades on locomotor, object control and overall TGMD-3, with the 2nd graders displaying highest mean scores, followed by 1st graders and kindergarteners. Follow-up tests suggested that high SES children displaying statistically significant higher mean scores than low SES students on all motor skill variables. Conclusion: Older children demonstrated higher motor competence levels, and those with high SES displayed higher motor skill levels than lower SES children.

Objective: The purpose of this investigation was to determine the differences in collegiate and recreationally trained soccer players in sprint, vertical jump, and balance performance. Methods: Twenty-one soccer players, twelve Division II collegiate and nine recreationally trained volunteered to participate. Session one acted as a familiarization day, where the participants were familiarized with testing day protocols. During testing day, participants performed a dynamic warm-up, followed by balance measurements, three countermovement vertical jumps, and pro-agility shuttle test. Results: There were no significant (p>0.05) differences between groups in the all balance variables. Collegiate soccer players had a significantly (p<0.05) greater peak velocity in vertical jump then recreationally trained soccer players. There were significant differences (p<0.05) between groups for maximum for split velocities, where collegiate soccer players were greater than recreationally trained soccer players. There were no significant (p>0.05) differences in groups in all other variables. Conclusion: These results indicate that collegiate, Division II, soccer players had greater vertical jumping and sprinting velocities when compared to recreationally trained soccer players. These results may have been impacted by the lack of resistance training background in either of the two groups. With the addition of more time on a collegiate resistance training program, it is very likely the Division II athletes will see a significant increase in all balance, sprint, and vertical jump performance measures compared to recreationally trained players who receive little to no specialized resistance training.

Background: Gait retraining using real-time biofeedback (RTB) may have positive outcomes in decreasing knee adduction moment (KAM) in healthy individuals and has shown equal likelihood in patients with knee osteoarthritis (OA). Currently, there is no consensus regarding the most effective gait modification strategy, mode of biofeedback or treatment dosage. Objective: The purpose of this review was: i) to assess if gait retraining interventions using RTB are valuable to reduce KAM, pain, and improve function in individuals with knee osteoarthritis, ii) to evaluate the effectiveness of different gait modifications and modes of RTB in reducing KAM in healthy individuals, and iii) to assess the impact of gait retraining interventions with RTB on other variables that may affect clinical outcomes. Methods: Seven electronic databases were searched using five search terms. Studies that utilized any form of gait retraining with RTB to improve one or a combination of the following measures were included: KAM, knee pain, and function. Twelve studies met the inclusion criteria, evaluating eleven distinctive gait modifications and three modes of RTB. Results: All but one study showed positive outcomes. Self-selected and multi-parameter gait modifications showed the greatest reductions in KAM with visual and haptic RTB being more effective than auditory. Conclusions: Current evidence suggests that gait modification using RTB can Positively alter KAM in asymptomatic and symptomatic participants. However, the existing literature is limited and of low quality, with the optimal combination strategies remaining unclear (gait and biofeedback mode). Future studies should employ randomized controlled study designs to compare the effects of different gait modification strategies and biofeedback modes on individuals with knee OA.

Background of Study: The implementation of a muscular endurance resistance training (MERT) program has been shown to be beneficial in augmenting the onset of blood lactate accumulation (OBLA). However, the effects of MERT on local muscular endurance has not been investigated. Objectives: The purposes of the current study were to investigate the effects of 4 weeks of MERT on local muscular endurance, and the relationship between OBLA and fatigue index (FI). Methods: Endurance trained males were randomly designated to either the experimental (EX) or control (CON) group: 9 EX and 8 CON. All participants continued current aerobic training. Baseline measures included OBLA, 1 repetition maximum (1RM) for: leg press (LP), leg curl (LC), and leg extension (LE). FI of the quadriceps was assessed via a dynamometer and the Thorstesson protocol. In addition, the EX group performed supervised MERT training for four weeks. A two way ANOVA was used to assess group and time differences in performance measures. The relationship between OBLA and FI was assessed using Pearson’s Correlation. Results: No significant group differences were observed in all baseline measurements (p>0.05). There were no significant group or time differences for OBLA and FI (p>0.05). Pearson’s correlation revealed no significant relationship (p>0.05, r=<0.01) existed between FI and OBLA. Conclusions: It was observed that four weeks of MERT provided an insufficient stimulus to improve OBLA and FI, and no significant relationship existed between OBLA and FI. Athletes using MERT should include additional mesocycles for favorable adaptations to local muscular endurance and OBLA.

Background: American football and the athletes that participate have continually evolved since the sport’s inception. The fluidity of the sport, as well as the growth of the body of knowledge pertaining to American football, requires evolving training techniques. While performance data is being garnered at very high rates by elite level sports organizations, the limiting factor to the value of data can be the limited known uses for the data. Objective: This study introduces a technique that can be used in tandem with data collected from wearable technology to better inform training decisions. Method: The K-means clustering technique was used to group athletes from two seasons worth of data from an NCAA Division 1 American football team that is in the “Power 5.” The data was obtained using Catapult Sports OPTIMEYE S5 TM in games played against only other “Power 5” programs. This data was then used to create average game demands of each student-athlete, which was then used to create training groups based upon individual game demands as previously mentioned. Results: The resultant groupings from the single-season analyses of seasons one and two showed results that were similar to traditional groupings used for training in American football, which worked as validation of the results, while also offering insights on individuals that may need to consider training in a non-traditional group based upon their game demands. Conclusion: This technique can be brought to `athletic training and be useful in any organization that is dealing with training multitudes of athletes.

Background: Over 2.7 million people suffer traumatic brain injuries (TBIs) annually in the United States. TBI involves the application and generation of external forces and impulse loads respectively to the head whereby the brain moves relative to the skull. Despite numerous studies, further understanding of TBIs is necessary, requiring consistent attention. Objective: The purpose of this article is to investigate the history of American football helmets and provide an academic and practitioner review as it relates to TBIs. This study is a literature review that also considers perspectives from an autoethnographic frame. Method: An extensive literature review was performed to assess the history of TBI as it relates to American football. This article evaluates helmet design optimization and American football safety as well as an exploration into the sports’ education methods for players and staff alike. Results: Despite developing helmet designs that can better attenuate impact forces, reducing linear and rotational movement, the skull and brain move very differently relative to one another. Helmet designs and tools for measuring forces require further validation techniques to determine resultant forces and movement for the brain. Current biomechanics research lacks sufficient methodology for defining TBI thresholds, making helmet optimization difficult. Conclusion: According to past research, no helmet can eliminate all TBI risk; however, processes are in place lead by the National Football League (NFL) and NFL Players Association to educate players, coaches, and staff at all levels of competition of the protective capabilities of available helmet options.

Background: This study is concerned with the special case of a putted ball intersecting a standard golf hole at its diameter. The velocity of the ball at the initial rim of the hole is termed the launch velocity and depending upon its value the ball may either be captured or it may escape capture by jumping over the hole. The critical value of the launch velocity (V) is such that lesser values result in capture while greater values produce escape. Purpose: Since the value of the V entered prominently in some theoretical studies of putting, the aim of the current study is to provide an original re-evaluation of V and to contrast our results with existing results. Method: This analytical analysis relies on trigonometry in conjunction with Newtonian mechanics and the mathematics of projectiles. The results of a recent study into the mathematics of a bouncing ball which included the notions of restitution and friction were also employed in the analysis. Results: If bouncing and slipping do not occur when the ball hits the far rim of the hole our analysis produces a value of V of 1.356 m/s. When bouncing and slipping are present we find that V is at least 1.609 m/s but increases beyond this value as slipping and friction become greater. Useful relations which relate the dynamics and geometry of the ball to V are provided. Conclusion: Since ambient conditions may influence the extent of bounce and slippage we conjecture that the value of V is not unique.

Background: The game of water polo has become more familiar to all the athletes and coaches as the time has passed. It has been played as a sport for more than a century Although anatomical shoulder movement strength balance is a crucial factor in overhead throwers’ performance, it has not been studied extensively in the previous research. Objective: This study examined shoulder movement imbalance in bilateral and dominant anterior-posterior shoulder among 42 elite water polo players in Malaysia. Method: The t-test analyses of data obtained through several tests proved that water polo players had statistically significant difference between their right hand anatomical shoulder movement strength and their left hand anatomical shoulder movement strength in all eight shoulder movements, i.e. Flexion, Extension, Abduction, Adduction, Horizontal Adduction, Horizontal Abduction, Rotation and External Rotation. Results: The results of this study showed that there are significant differences of anatomical shoulder movement strength in both bilateral and Anterior-posterior shoulder movement among water polo players. The statistics results for bilateral shoulder movement of Flexion (t= 136.09 and p

Background: Hip muscle weakness is associated with higher peak knee valgus angles (VA) during drop vertical jumps (DVJ) and linked to ACL injury risk. Objective: To determine if isometric strengthening (IST) of the hip extensor, abductor, and external rotator muscle groups would reduce VA exhibited during a DVJ. Methodology: Fourteen female volleyball players (7 training (TG), 7 control (CG), VA≥9˚ during DVJ) participated. Pre- and post-test gluteal, quadriceps and hamstring strength were measured with a digital force gauge. Three-dimensional kinematics were collected during 15 DVJ trials. TG participated in a 6-week IST program that targeted the hip extensor, abductor, and external rotator muscle groups. Two-way mixed ANOVAs compared mean differences of VA and strength. Single-participant analyses examined if athlete-specific adaptations went undetected in the analyses of aggregated data. Results: TG hip extension, abduction, and knee flexion strength increased, respectively, by 20.5%, 27.5% and 23.5% (P<0.05). No group-level changes in VA were detected. Unilateral VA decreased for 5 TG participants, and bilateral VA decreased in 2 TG participants. Conclusions: IST increased isometric hip muscle strength, but its effect on VA is inconclusive based on group-level analyses. Using single-participant designs, future studies should assess IST and/or dynamic resistance/neuromuscular training in a larger sample to determine its effect on ACL injury risk factors.

Background: Bat velocity, attack angle, and vertical angle are common variables that coaches and players want to evaluate during their baseball or softball swing. Objective: The purpose of this study was to investigate and validate a baseball bat handle sensor against motion capture using recreational baseball and softball athletes for bat velocity, attack angle, and vertical angle. Methods: This single visit cross-sectional experimental design study utilized eighteen recreational baseball and softball players (ten males and eight females, age: 20.70 ± 1.69 years, height: 170.74 ± 5.69 cm, weight: 77.97 ± 12.30 kg) were recruited. Bat velocity, attack angle, and vertical angle from the bat handle sensor and 12-camera motion capture system were collected and compared using a two-tailed paired t-test. Results: Differences were statistically significant, showing that 95% of the time, the bat handle sensor overestimated the bat velocity by 1.92 to 2.77 m/s, underestimated the attack angle by -3.46 to -1.96°, and overestimated the vertical angle by 1.64 to 3.21°, compared to the motion capture system. Conclusion: The bat velocity and vertical angle were overestimated, while the attack angle was underestimated by the bat sensor. The information presented in this study can be viable information for coaches and players when utilizing the baseball bat handle sensor technology for training, practice, or in-game situations.

Background: Dynamic knee valgum is a major risk factor in ligamentous injuries of the knee. Different sports have higher rates of knee ligament injury than others and females experience knee non-contact ligament injuries at higher rates than their male counterparts. Objectives: The purpose of this study was to investigate the lower extremity biomechanics of genu valgum in female collegiate athletes of various sports while performing a drop jump test. This information may provide those designing individualized prevention programs assistance in reducing risk of knee ligamentous injury during jumping tasks. Methods: Current members of Idaho State University’s women’s basketball, soccer, and softball teams were evaluated for this study. Thirty-seven athletes participated. Motion capture reflective markers were placed bilaterally on the lower extremities to allow for analysis of knee biomechanics during a double-leg drop jump test. The angles of knee valgum in the frontal plane were calculated and analyzed between sport groups. Results: Female athletes of different sports displayed statistically significant differences in knee angles for both right, and left knees. Post hoc analysis with a Bonferroni adjustment revealed that basketball players utilized a more valgus right knee angle compared to both soccer and softball players and a more varus left knee angle compared with softball players. Conclusions: Our study suggests that collegiate-level female basketball players have an increased risk of right leg non-contact knee ligament injury during jump landing maneuvers when compared to collegiate level softball and soccer players due to increased knee valgus movements during the drop jump test. Collegiate-level female basketball players may benefit from biomechanical exercise interventions designed to decrease right knee valgus moments in jumping and landing to decrease their risk of injury.

Background: Nowadays, different types of exercise machines are being used in the field of athletic training, recreation, post-injury and post-operation rehabilitation. Leg press is a commonly-used one that retrains muscles and simulates natural functional activities. In this activity, feet are in contact with a footrest to exert muscular forces. In addition, the footrest inserts reactive forces to feet and from the feet load would transfer to structures that are more proximal. Any misalignment in foot structure may interfere its function. Objective: The aim of this study was to assess the effect of shoes and using a prefabricated medial arch support on the activity of Tibialis anterior and medial gastrocnemius muscles while doing leg press exercise in normal feet subjects. Method: 14 men with normal Medial Longitudinal Arch and normal Body Mass Index aged between 18-35 years old, with at least 6 months experience of doing leg press volunteered to participate in this study. Medial gastrocnemius and Tibialis anterior activity were measured by surface electromyography while doing leg press with 70% of subjects 1 Repetition Maximum. To increase accuracy, motion was divided into knee flexion and knee extension phases. Peak Amplitude, Time to Peak Amplitude and Root Mean Square variables were used for analysis. Wilcoxon nonparametric test was used to compare the results. Results: No statistically significant difference was found in the electromyographic parameters of Medial gastrocnemius nor Tibialis anterior in any phases of motion, except for an increase in Tibialis anterior time to peak amplitude in shod condition compared with barefoot in knee extension phase of motion (p-value=0.008) and Tibialis anterior RMS in knee flexion phase in orthotic condition compared to shod (p-value=0.03). Conclusion: It seems that in high loads shoes or medial arch supports cannot change electromyographic parameters in Medial gastrocnemius nor Tibialis anterior in any phase of motion while working with leg press device.

Background: Plyometric training (PT) are performed in different hard surfaces like dry land, hard court or grassy turf which is at the same time susceptible to muscle and joint injury of the lower limbs. To avoid this risk Aqua-based training gradually has become popular to the trainers. Therefore, in the present study the PT were conducted in an aquatic medium. Objective: The purpose of the present study was to investigate the effect of Aquatic plyometric training on speed and explosive leg strength ability of the young Indian athletes. Method: This study was quasi-experimental in nature. Twenty-four (N = 24) athletes aged between 14-16 years were selected. They were equally grouped into two: i) Aquatic Plyometric Training Group (APTG, N=12), and ii) Control Group (CG, N=12). Both the groups were involved in regular physical activity as usual in their academy which was not under the control of the researchers, however, in addition to that APTG underwent an aqua-based Plyometric training for fourteen weeks. The dependent variables were speed and explosive leg strength. Baseline (pre) and post intervention mean values for APTG and CG were analyzed through ANCOVA. The F-values were tested at p0.05 level of significance. Results: The APTG improved significantly with respect to the CG in speed (F = 70.890; p 0.00001) and explosive leg strength (F = 32.553; p 0.00001). Conclusion: Aquatic Plyometric Training was found as an effective training means for the development of speed and explosive leg strength of the athletes belongs to the age group of 14-16 years.

Background: Recreational athletes can select their desired footwear based on personal preferences of shoe properties such as comfort and weight. Commonly worn running shoes and cleated footwear with similar stud geometry and distribution are worn when performing sport-specific tasks such as a side-step cutting maneuver (SCM) in soccer and American football (hereafter, referred to as football). The effects of such footwear on injury mechanics have been documented with less being known regarding their effect on performance. Objective: The purpose of this study was to examine performance differences including peak ground reaction forces (pGRF), time-to-peak ground reaction forces (tpGRF) and the rate of force development (RFD) between football cleats (FB), soccer cleats (SOC), and traditional running sneakers (RUN) during the braking and propulsive phases of a SCM. Methodology: Eleven recreationally active males who participated in football and/or soccer-related activities at the time of testing completed the study. A 1 x 3 [1 Condition (SCM) x 3 Footwear (RUN, FB, SOC)] repeated measures ANOVA was utilized to analyze the aforementioned variables. Results: There were no significant differences (p > 0.05) between footwear conditions when comparing pGRF, tpGRF, or RFD in either the braking or propulsive phases. Conclusion: The results suggest that the studded and non-studded footwear allowed athletes to generate similar forces over a given time frame when performing a SCM.

The purpose of the current investigation was to test the feasibility of utilizing pedometer data collected during gamelike practices to quantify the number of impacts experienced by varsity athletes. Forty-four varsity basketball and soccer athletes wore pedometers and the total number of steps and practice time were recorded during two different practices of similar intensity. The normalized step count, calculated as the total numbers of steps divided by the practice time, was obtained from the first practice and was used to estimate the step count for the second practice. The estimated step count was then compared to the actual step count, as determined from the pedometers. The mean percent difference between actual and estimated step counts was under 25% for approximately 75% of all athletes with no significant difference between the estimated and actual number of steps. The presented results suggest that the pedometer-based method presented here is a feasible method for estimating the number of steps experienced by university varsity athletes.

Background: With advances in concussion research, an increasing amount of resources are being allocated to advancing football helmet technology. Objective: This study assesses the claim that a new modified helmet prototype provides greater field of view for the user as compared to a commonly worn helmet by players. Method: The helmets—Riddell SpeedFlex and the modified helmet—were compared based on user response time while performing a response test task using the FITLIGHT Trainer system, actual helmet field of view blockage, users’ subjective perception of field of view, and balance tests. Eighteen National Collegiate Athletic Association (NCAA) Division 1 American football student-athletes completed the response test task and questionnaire. Results: The results demonstrate evidence that the SpeedFlex helmet provided by the equipment staff significantly increases wearers’ response times, F(2,20) = 5.646, p < 0.05. Also, while the quantification of the field of view perception was similar across helmet types, the student-athlete participants perceived the modified helmet to have significantly more field of view while performing the response test task, 1.56 v. 2.56; p < 0.05 for frontal vision and 2.83 v. 5.39; p < 0.05 for peripheral vision. Conclusion: In addition to the findings, this study also lays out a response time test protocol using the FITLIGHT Trainer system that can be used for assessment of response time testing of football and other helmets in future studies.

Background: Fundamental movements (FM) of children influence the willingness to engage in physical activity (PA). Thus, proper FM skills are the foundation for a lifespan of PA. Objective: This study examined what factors may affect children’s PA in relation to FM pattern capabilities. Methods: The study examined the influence of SES when three low-income schools were provided additional PA opportunities on days PE was not taught. FM patterns in relation to object control (OC) and locomotor skill (LC) development were evaluated on K (n = 871), 1st (n = 893), and 2nd graders (n = 829) using the Test of Gross Motor Development-2 (TGMD-2) instrument (Ulrich, 2000). Schools were dichotomized and categorized as being low SES (n = 2008) and high SES (n = 578) status. Results: A significant relationship was revealed with LC (r = 0.264; p = 0.001), OC (r = 0.171; p = 0.001), and total TGMD-2 (r = 0.264; p = 0.001). Low and high SES schools significantly improved overall TGMD-2 scores. High SES schools children were significantly higher in LC [F, (2, 1272) = 29.31, p = 0.001], OC [F, (2, 1272) = 23.14, p = 0.001], and total TGMD-2 [F, (1, 1272) = 38.11, p = 0.001]. Conclusion: Low SES schools need to concentrate on PA-based activities to engage students in FM patterns, to help narrow the gap in FM capabilities. In addition, the increase in PA opportunities for lower SES schools could positively impact brain function, cardiovascular fitness, and overall well-being.

Background: Wearable technology use in sports has amassed increased attention in recent years. Technological advancements have provided less labor-intensive methods for practitioners and athletes to track kinematic movements, workload metrics, and biometric markers to assess performance and safety. As such, wearables research has spread to a variety of sports; however, the specific wearable technologies used in the rugby codes—rugby league and rugby union—have not been reviewed. Objective: Herein, we present a review that aims to understand the use of wearable technology for performance demand quantification and player health assessment in rugby league and rugby union. Method: We classify extant scientific wearable literature into four research categories: Prehabilitation (preventative rehabilitation), Performance, Rehabilitation, and Data Analysis. Results: Eighteen articles were found using predefined inclusion and exclusion criteria and were grouped into these four research categories. Through this review process, Global Positioning System or GPS-based wearables were found to be utilized more when compared to all other wearable devices associated with peer-reviewed studies for the sport of rugby. In general, wearables were found to be used to support player and practitioner efforts to promote health and ensure peak performance prior to competition. Wearables were also used to determine injury severity and mitigation strategies—such as collision monitoring—and to develop positional activity profiles. Conclusion: Data collected through wearable technology may enhance rugby conditioning programs by enabling the tracking of numerous aspects of training performance and safety in competitive match play. Future research is warranted for standardization of player evaluation and injury predictive modeling.

Background of Study: Associations between measures of body composition and vertical jump height have previously been established using a range of instrumentation and prediction equations. Limited data has presented using gold standard measurements for both variables Objective: This investigation sought to examination the relationship between total body and lower extremity measures of body composition and vertical jump performance using gold standard measurements within an athletic population. Methods: Using a cross-sectional, correlational research design fourteen collegiate female volleyball athletes completed body composition, three countermovement jumps (CMJ) and three squat jumps (SJ) analysis using DXA and force platforms. Results: High to very high positive relationships were seen between total body lean (p < 0.001) and fat mass (p < 0.05), lower extremity lean and fat mass (p < 0.01), and CMJ force and power. High negative relationships were present between total body fat percentage(p < 0.05), total fat mass (p < 0.01) and CMJ jump height. Relationships between all body composition variables and SJ performance tended to be weaker, with the exception of total body lean mass (p < 0.05), lower extremity lean mass, and power output (p < 0.01). Conclusions: These findings support much of the previous literature in that increases of mass have subsequent increases in force and power production; however caution should be taken will increases in mass coming from fat or lean tissue.

Background: Females combat sport athletes are likely to partake in rapid weight reduction strategies prior to competitions. Objective: The purpose of this study was to investigate the relationship between weight cutting habits of female combat sport athletes and the risk of developing the female athlete triad. Methods: 102 female combat sport athletes (amateur=40; professional=62; 28.8±4.5y), competing in boxing (n=30), kickboxing (n=12), and mixed martial arts (n=60), completed two questionnaires. An adapted version of the Rapid Weight Loss Questionnaire (RWLQ) was used to determine the severity of athletes’ weight cutting behaviors, and the Low Energy Availability in Females Questionnaire (LEAF-Q) was used to determine female athlete triad risk. Data was analyzed to determine correlations between LEAF-Q and RWLQ scores along with weight cutting behaviors. Scores were also compared between competition level and combat sports. Results: The results of this study showed that 38% of female combat sport athletes were at risk of developing the female athlete triad. Significant correlation between RWLQ and LEAF-Q scores (p=0.013; r=0.244, r2=0.060) were noted. A significant difference (p=0.006) between the RWLQ scores of amateurs and professionals was also noted, with professionals engaging in more severe weight cutting behavior. Mixed martial artists reported the highest RWLQ and LEAF-Q scores, which were significantly greater than boxers. No other correlations between LEAF-Q and weight cutting behaviors were noted. Conclusion: Despite a small effect size (r²=0.060), the findings of this study demonstrate that more severe weight cutting behaviors may increase the female athlete triad risk among female combat sport athletes.

Background: The overall physical and psychological development of a young athlete is crucial for the enjoyment of physical activity for a lifetime. Children, as well as parents, tend to focus on individual accomplishment in sport despite any other aspect of physical development or appropriate training. Objective: the pressure to excel in sport has all too often brought about negative consequences through specialization at an early age. Method: A review and commentary report on the impact of early sport specialization on the physical and psychological development of a young athlete. Conclusion: A long-term, activity and age-appropriate developmental model is essential to those involved in training young athletes. Sport specialization may be appropriate in unique situations but only after the development of specific skills, abilities, and psychological maturity. As sport professionals, parents and coaches should be educated the pros/cons of early sport specialization. Ultimately, the focus on sport participation should be to increase physical activity, psychological development, and appreciation for a lifetime.

Background: Assessing basketball shoe comfort and fit as personal protection equipment (PPE) at the collegiate level is unique. Objective: The purpose of Part II in this pilot study was to examine the effect of shoe design on the perception of comfort and fit after performing an acute series of jumps in elite male and female National Collegiate Athletic Association (NCAA) Division 1 basketball student-athletes. Method: A total of sixteen basketball student-athletes (six males, ten females) performed two rounds of acute series of four styled basketball jumps on two ForceDecksTM Force Platforms while trying to maximize jump height by tapping VertecTM Jump Vanes. The male student-athletes selected the AdidasTM Harden Vol. 3 and the AdidasTM SM Pro basketball shoes. The female student-athletes selected the Adidas Harden Vol. 3 and the Adidas Captain Marvel basketball shoes. Upon completion of each round of jumps, the student-athlete recorded their perception of comfort on a 110mm Visual Analog Scale (VAS) and fit on a seven-point Likert rating scale based against their most comfortable basketball shoes ever worn. Results: Results of this pilot study reported, on average, the male student-athletes preferred comfort and fit of the Adidas SM Pro basketball shoes and the female student-athletes preferred the Adidas Harden Vol. 3 basketball shoe, though differences were non-significant at p > 0.05. Conclusion: The use of a human factors assessment tool to evaluate basketball shoe comfort and fit and the influence of rated comfort and fit parameters on basketball jumping performance proved viable.

Background: The body of research on field based player-surface interaction consists of some contradictory findings and the comparison of male and female physiological responses on different surfaces is limited. Objective: The study investigates the influence of surface properties on sprint running before and after completing a muscle fatiguing intervention. Methodology: Muscle activity was recorded using surface electromyography (EMG). The vastus medialis (VM), biceps femoris (BF), medial head of the gastrocnemius (MG), and the tibialis anterior (TA) sites were selected for analysis. The mechanical properties (MPs) of each field were shown to be different using ASTM F-3189 protocol. Results: A statistically significant three-way repeated measures ANOVA interaction between field properties, sprint trial and muscle groups was determined, F(3,36) = 10.82, p = .006, ηρ2 = .474. Further analyses revealed an interaction effect between field properties and sprint trial, F(1,12) = 26.57, p = .001, ηρ2 = .689, between muscle groups and field properties F(1,12) = 8.78, p = .012, ηρ2 = .422 and between muscle group and sprint trial F(1,12) = 7.29, p = .019, ηρ2 = .378. In addition, pre-intervention mean sprint time was less on the field possessing more energy return by 9.1%. Post-intervention sprint test results show a significant difference for BF peak muscle activity on the field displaying greater force attenuation. Conclusion: Both pre and post intervention sprint results suggest time-dependent properties associated with a sport field could potentially influence muscle activation patterns differently for males and females.