Physiological and Performance Correlates of Squash Physical Performance

The physiological and performance attributes of elite squash players were investigated. Thirty-one players (21 males, world ranking [WR] 42-594; 10 females, WR 7-182) completed a battery of fitness tests which included an aerobic squash-specific physical performance test (SPPT), repeated-sprint ability (RSA), change-of-direction speed (COD), acceleration (5-m sprint), body composition and force development (countermovement jump) assessments. The SPPT provided a finishing lap score, V̇O2max, average movement economy and the lap corresponding to a blood lactate concentration of 4 mM.L-1. Players were ranked and assigned to HIGH or LOW performance tiers. Two-way ANOVA (performance level*sex) revealed higher ranked players performed better (p < 0.05) for SPPT final lap (d = 0.35), 4 mM.L-1 lap (d = 0.52) and COD (d = 0.60). SPPT displayed a ‘very-large’ correlation with 4 mM.L-1 lap (r = 0.86), ‘large’ correlations with COD (r = 0.79), RSA (r = 0.79), sum-of-7 skinfolds (r = 0.71) and V̇O2max (r = 0.69), and a ‘trivial’ correlation with average movement economy (r = 0.02). Assessments of cardiovascular fitness (i.e. 4 mM.L-1 lap), RSA, COD and body composition appear highly pertinent for performance profiling of squash players. Regular, submaximal assessment of the 4 mM.L-1 lap during the SPPT may offer a practical athlete monitoring approach for elite squash players.

Moderate and Severe Injuries at Five International Olympic-Style Wrestling Tournaments during 2016-2019

As a contact sport, wrestling may result in injuries. Based on the severity, they are classified as mild, moderate, severe and critical. All injuries occurring at international competitions are documented in a cloud-based surveillance system. The purpose of this study was to analyze the incidence and characteristics of moderate and severe (including critical) wrestling injuries that occurred during five international Olympic-style wrestling competitions in 2016-2019. Three Wrestling World Championships and two European Wrestling tournaments were organized by the Hungarian Wrestling Federation in 2016-2019. A total of 2483 wrestlers in three Olympic wrestling styles have competed in 3007 matches. Data from all injuries were recorded and analyzed to define rates, locations, types and severity, and to compare with previous reports. A total of 53 wrestlers sustained 55 injuries, which is equivalent to an overall injury incidence rate of 9.1‰ (9.1/1000 athletic exposures). Greco-Roman and Women Wrestling had the same injury incidence rate, while Freestyle had a lower one (9.5‰ versus 8.5‰). The injury proportion by regions and anatomic locations were on head and face 29.1%, spine and trunk 16.4 % and the upper-and-lower extremity injuries equally 27.3%. The most common types of injuries included ligament lesions, joint injuries, skin lacerations, and contusions. Five wrestlers (0.8‰) sustained strangulation or concussion. Wrestling injury rates during United World Wrestling competitions are not high, but when happen they can be serious. Despite relatively low incidence rate of injuries, there is a need for continuous education for medical teams, referees and coaches to avoid wrestling injuries.

Sex Moderates the Relationship between Perceptual-Motor Function and Single-Leg Squatting Mechanics

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R2 = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R2 = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R2 = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R2 = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

Early Superimposed NMES Training is Effective to Improve Strength and Function Following ACL Reconstruction with Hamstring Graft regardless of Tendon Regeneration

The study aimed at investigating the effects of neuromuscular electrical stimulation superimposed on functional exercises (NMES+) early after anterior cruciate ligament reconstruction (ACLr) with hamstring graft, on muscle strength, knee function, and morphology of thigh muscles and harvested tendons. Thirty-four participants were randomly allocated to either NMES+ group, who received standard rehabilitation with additional NMES of knee flexor and extensor muscles, superimposed on functional movements, or to a control group, who received no additional training (NAT) to traditional rehabilitation. Participants were assessed 15 (T1), 30 (T2), 60 (T3), 90 (T4) and at a mean of 380 days (T5) after ACLr. Knee strength of flexors and extensors was measured at T3, T4 and T5. Lower limb loading asymmetry was measured during a sit-to-stand-to-sit movement at T1, T2, T3, T4 and T5, and a countermovement-jump at T4 and T5. An MRI was performed at T5 to assess morphology of thigh muscles and regeneration of the harvested tendons. NMES+ showed higher muscle strength for the hamstrings (T4, T5) and the quadriceps (T3, T4, T5), higher loading symmetry during stand-to-sit (T2, T3, T4, T5), sit-to-stand (T3, T4) and countermovement-jump (T5) than NAT. No differences were found between-groups for morphology of muscles and tendons, nor in regeneration of harvested tendons. NMES+ early after ACLr with hamstring graft improves muscle strength and knee function in the short- and long-term after surgery, regardless of tendon regeneration.

Sex Differences in Neck Strength Force and Activation Patterns in Collegiate Contact Sport

The purpose of this study was to assess changes in cervical musculature throughout contact-heavy collegiate ice hockey practices during a regular season of NCAA Division III ice hockey teams. In this cross-sectional study, 36 (male n = 13; female n = 23) ice hockey players participated. Data were collected over 3 testing sessions (baseline; pre-practice; post-practice). Neck circumference, neck length, head-neck segment length, isometric strength and electromyography (EMG) activity for flexion and extension were assessed. Assessments were completed approximately 1h before a contact-heavy practice and 15 min after practice. For sternocleidomastoid (SCM) muscles, males had significantly greater peak force and greater time to peak force versus females. For both left and right SCMs, both sexes had significantly greater peak EMG activity pre-practice versus baseline, and right (dominant side) SCM time to peak EMG activity was decreased post-practice compared to pre-practice. There were no significant differences for EMG activity of the upper trapezius musculature, over time or between sexes. Sex differences observed in SCM force and activation patterns of the dominant side SCM may contribute to head stabilization during head impacts. Our study is the first investigation to report changes in cervical muscle strength in men’s and women’s ice hockey players in the practical setting.

Injuries in Medium to Long-Distance Triathlon: A Retrospective Analysis of Medical Conditions Treated in Three Editions of the Ironman Competition

Triathlon’s popularity is rapidly increasing, and epidemiological data relating to its related medical conditions is crucial to the development of proper medical plans and safety guidelines for it. This study examined the data from the medical reports collected during three consecutive editions of Ironman Italy, from 2017 to 2019. Out of 10,653 race-starters, 3.3% required medical attention sustaining 472 medical conditions. A significantly higher injury risk was found for females versus males (χ2 = 9.78, p = 0.02) and in long-distance (IR: 4.09/1,000hours) rather than in Olympic/middle distance races (IR: 1.75/1,000hours). Most (68.4%) conditions (including muscular exhaustion, hypothermia, and dehydration) were systemic, whilst only 10.2% were acute traumatic injuries. Of a total of 357 triathletes requiring medical assistance, 8.1% were a candidate for hospitalisation. The equipment and personnel that are required for the medical assistance in future triathlon events were estimated based on Maurer’s algorithm, and ten practical recommendations for triathlon medical support were formulated.

The Effects of Visual Feedback on Performance in Heart Rate- and Power-Based-Tasks during a Constant Load Cycling Test

Performance feedback can be essential for cyclists to help with pacing their efforts during competitions and also during standardized performance tests. However, the choice of feedback options on modern bike computers is limited. Moreover, little research on the effectiveness of the currently used feedback methods is available. In this study, two novel feedback variants using a bar or a tacho to visualize targets and deviation from targets were compared to a classic design using only numbers. Participants (6 female and 25 male trained to well-trained athletes) completed a protocol consisting of three heart rate-based tasks and one power-based task. The displays were compared with respect to their ability to guide athletes during their trials. Results showed lower root mean square error (RMSE) of the novel variants, but no significant effect of feedback variant on RMSE was found for both tasks (p > 0.05). However, when comparing the feedback variants on a person to person basis, significant differences were found for all investigated scenarios (p < 0.001). This leads to the conclusion that novel feedback variants can improve athletes’ ability to follow heart rate-based and power-based protocols, but even better results might be achieved by individualizing the feedback.

The Effect of Ankle Position on Peak Eccentric Force during The Nordic Hamstring Exercise

Peak eccentric force during the Nordic hamstring exercise (NHE) is recognized as a predictive factor for hamstring strain injury (HSI). During the NHE, the knee flexor muscles are eccentrically contracting to resist the knee joint extension. Therefore, it is thought that the action of the gastrocnemius muscle, and thus the ankle position, influences peak eccentric force during the NHE. However, the effect of ankle position on peak eccentric force during the NHE remains unclear. Therefore, we investigated the effect of ankle position on peak eccentric force during the NHE in a cohort of 50 healthy young male rugby players (mean age, 18.7 ± 1.2 years; mean body mass, 81.7 ± 15.2 kg; height, 1.72 ± 0.06 m) with no history of HSI. Each participant performed NHE strength testing with the ankle dorsiflexed or plantarflexed position and was instructed to fall forward as far as possible within 3 s. Peak eccentric force, reported relative to body mass (N/kg), of both legs was recorded, and the mean values of both legs were compared in both ankle positions. The mean peak eccentric force was significantly greater with the ankle plantarflexed position than the dorsiflexed position (3.8 ± 1.1 vs. 3.5 ± 1.1 N/kg, respectively, p = 0.049). These results indicate that ankle position should be carefully considered when measuring peak eccentric force during the NHE and performing NHE training.

A Combination of Ice Ingestion and Head Cooling Enhances Cognitive Performance during Endurance Exercise in the Heat

his study assessed the effectiveness of head cooling during exercise in the heat on cognitive performance, either alone or with ice ingestion. Ten healthy males, non-acclimatized to heat, ran (70% V̇O2peak) for 2×30 min in heat (35 ± 0.9°C, 68.2 ± 6.9% RH). Participants completed 3 trials: 10 min of head cooling during exercise (HC); precooling with crushed ice (7gikg-1) and head cooling during exercise (MIX); or no-cooling/control (CON). Working memory was assessed using the automated operation span task (OSPAN) and serial seven test (S7). Following MIX, S7 scores were improved compared to CON (12 ± 9.5, p = 0.004, d = 1.42, 0.34-2.28) and HC (4 ± 5.5, p = 0.048, d = 0.45, -0.47 to 1.3) during exercise. Moderate to large effect sizes were recorded for S7 and OSPAN following MIX and HC compared to CON, suggesting a tendency for improved cognitive performance during exercise in heat. Following precooling (MIX), core body temperature (Tc) and forehead temperature (Th) were lower compared to baseline (-0.75 ± 0.37°C, p < 0.001; -0.31 ± 0.29°C, p = 0.008, respectively) but not in HC or CON (p > 0.05). Thermal sensation (TS) was lower in MIX and HC compared to CON during exercise (p < 0.05). The reduction in Tc, Th and TS with MIX may have attenuated the effect of heat and subsequently improved working memory during exercise in heat.

Myofascial Treatment Techniques on the Plantar Surface Influence Functional Performance in the Dorsal Kinetic Chain

Prior studies have shown that self- and manual massage (SMM) increases flexibility in non-adjacent body areas. It is unclear whether this also influences performance in terms of force generation. Therefore, this study investigated the effect of SMM on the plantar surface on performance in the dorsal kinetic chain. Seventeen young participants took part in this within-subject non-randomized controlled study. SMM was applied on the plantar surface of the dominant leg, but not on the non-dominant leg. A functional performance test of the dorsal kinetic chain, the Bunkie Test, was conducted before and after the intervention. We measured the performance in seconds for the so-called posterior power line (PPL) and the posterior stabilizing line (PSL). The performance of the dominant leg in the Bunkie Test decreased significantly by 17.2% from (mean ± SD) 33.1 ± 9.9 s to 27.4 ± 11.1 s for the PPL and by 16.3% from 27.6 ± 9.8 s to 23.1 ± 11.7 s for the PSL. This is in contrast to the non-dominant leg where performance increased significantly by 5.1% from 29.7 ± 9.6 s to 31.1 ± 8.9 s for the PPL and by 3.1% from 25.7 ± 1.5 s to 26.5 ± 1.7 s for the PSL. SMM interventions on the plantar surface might influence the performance in the dorsal kinetic chain.