Recreational Athletes Research Articles

Kiteboarding Injuries

The aim of this paper was to determine the type and frequency of injuries in kiteboarding, and to define causes of injuries in recreational and professional athletes engaged in kiteboarding. The research was conducted on the sample of 93 kiteboarders, of which 74 were male and 19 were female. Online questionnaire was applied with clearly defined completing instructions. In overall sample of examinees (93), there were 51 who were injured during kiteboarding. Out of total percentage of injured (54.8%), as many as 30.1% had more than one injury. Depending on the method of initial learning and training, 70% of examinees who were self-taught were injured, among those who were taught by a friend with kiteboarding experience 68.18% were injured, then there were 58.82% of injured among those who passed the kiteboarding course with an instructor without a valid license, and, finally, the smallest percentage of injured, 43,18%, among those who took the kiteboarding course with an instructor having a valid license. The most frequent injuries are foot and knee injuries (59.65%) and more than half of injuries (57.91%) is related to strains of ligaments and muscles. Most of the injuries happen during the performance of more advanced technical elements, particularly jumps (33.3 %), while the second most frequent cause of injuries is insufficient kite control (23.7%). Kiteboarders taught by licensed instructors had the smallest risk of injury, while the greatest risk of injury was for self-taught individuals. Mentioned data clearly suggests how important it is to take a verified course with educated instructors to reduce the risk of injuries to a minimum.

Low rates of myocardial fibrosis and ventricular arrhythmias in recreational athletes after SARS-CoV-2 infection.

High rates of cardiac involvement were reported in the beginning of the coronavirus disease 2019 (COVID-19) pandemic. This led to anxiety in the athletic population. The current study was set up to assess the prevalence of myocardial fibrosis and ventricular arrhythmias in recreational athletes with the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Consecutive adult recreational athletes (≥18 years old, ≥4 h of mixed type or endurance sports/week) underwent systematic cardiac evaluation after a prior confirmed COVID-19 infection. Evaluation included clinical history, electrocardiogram (ECG), 5-day Holter monitoring, and cardiac magnetic resonance (CMR) imaging with simultaneous measurement of high-sensitive cardiac Troponin I. Data from asymptomatic or mildly symptomatic athletes (Group 1) were compared with those with moderate to severe symptoms (Groups 2-3). Furthermore, a comparison with a historical control group of athletes without COVID-19 (Master@Heart) was made. In total, 35 athletes (18 Group 1, 10 female, 36.9 ± 2.2 years, mean 143 ± 20 days following diagnosis) were evaluated. The baseline characteristics for the Group 1 and Groups 2-3 athletes were similar. None of the athletes showed overt myocarditis on CMR based on the updated Lake Louise criteria for diagnosis of myocarditis. The prevalence of non-ischemic late gadolinium enhancement [1 (6%) Group 1 vs. 2 (12%) Groups 2-3; p = 0.603] or ventricular arrhythmias [1 Group 1 athlete showed non-sustained ventricular tachycardia (vs. 0 in Groups 2-3: p = 1.000)] were not statistically different between the groups. When the male athletes were compared with the Master@Heart athletes, again no differences regarding these criteria were found. In our series of recreational athletes with prior confirmed COVID-19, we found no evidence of ongoing myocarditis, and no more detection of fibrosis or ventricular arrhythmias than in a comparable athletic pre-COVID cohort. This points to a much lower cardiac involvement of COVID-19 in athletes than originally suggested.

Unanticipated mid-flight external trunk perturbation increased frontal plane ACL loading variables during sidestep cuttings

ABSTRACT Unanticipated trunk perturbation is commonly observed when anterior cruciate ligament (ACL) injuries occur during direction-changing manoeuvres. This study aimed to quantify the effect of mid-flight medial-lateral external trunk perturbation directions/locations on ACL loading variables during sidestep cuttings. Thirty-two recreational athletes performed sidestep cuttings under combinations of three perturbation directions (no-perturbation, ipsilateral-perturbation, and contralateral-perturbation relative to the cutting leg) and two perturbation locations (upper-trunk versus lower-trunk). The pushing perturbation was created by customised devices releasing a slam ball to contact participants near maximum jump height prior to cutting. Perturbation generally resulted in greater peak vertical ground reaction force and slower cutting velocity. Upper-trunk contralateral perturbation showed the greatest lateral trunk bending away from the travel direction, greatest peak knee flexion and abduction angles, and greatest peak internal knee adduction moments compared to other conditions. Such increased ACL loading variables were likely due to the increased lateral trunk bending and whole-body horizontal velocity away from the cutting direction caused by the contralateral perturbation act at the upper trunk. The findings may help understand the mechanisms of indirect contact ACL injuries and develop effective cutting techniques for ACL injury prevention.

Risk of low energy availability and level of nutrition knowledge in recreational trail runners in Aotearoa/New Zealand

Trail running is an endurance sport growing in popularity. It is characterised by long event durations and extreme environments that are likely to result in high exercise energy expenditure. Energy availability is defined as the amount of energy available to support normal physiological functions after subtracting the energy cost of exercise from energy intake. Insufficient energy intake, increased exercise, or a combination of both can result in a state of low energy availability (LEA). While research shows a weak positive association between nutrition knowledge and diet quality, results are conflicting regarding associations between nutrition knowledge and LEA. Research has demonstrated a high prevalence of risk of LEA (~33%-85%) among both elite and recreational athletes, across both sexes and in endurance sports such as running. However, little is known about risk of LEA and nutrition knowledge in trail runners. The aim of this study was to determine the risk of LEA prevalence in recreational trail runners and investigate associations with nutrition knowledge. Risk of LEA was assessed using the ‘Low Energy Availability in Females Questionnaire’ (LEAF-Q)(1), and the ‘Low Energy Availability in Males Questionnaire’ (LEAM-Q)(2). Nutrition knowledge was measured via the ‘Platform for Evaluating Athlete Knowledge in Sports – Nutrition Questionnaire’ (PEAKS-NQ)(3). Demographics and trail-running experience questions were integrated into the survey. Data was analysed in SPSS version 29 (IBM Corporation). Comparisons between groups (e.g. ‘low risk’ vs ‘not low risk’) were performed using a chi-square test for categorical variables, and an independent samples t-test for continuous variables. The final survey sample was 217 (140 females, 42.01 ± 10.72 years; 77 males, 47.86 ± 12.05 years) for the LEAF-Q, LEAM-Q, and trail running questions; and 152 for the PEAKS-NQ. Thirty-one percent of females (n = 43) were classified as ‘not low risk’ of LEA based on the LEAF-Q cut-off of ≥8. Twenty-three percent of males (n = 18) were identified as having low sex drive, a marker of LEA risk. The LEAF-Q/sex drive score was higher in those ‘not at low risk’ (10.72 ± 2.28/4.50 ± 1.95) compared to those at low risk (3.94 ± 2.34/1.53 ± 1.12, p<0.001). Three quarters of general nutrition knowledge responses were correct (females, 78.60 ± 10.09%; males, 75.78 ± 10.67%). However, sports nutrition scores were lower (females, 66.31 ± 13.44%; males, 63.18 ± 15.53%) with the lowest mean scores observed for ‘fuel for during events’. There was no significant association between nutrition knowledge and risk of LEA in both sexes. The findings suggest that recreational trail runners are a group of active individuals who are at risk of LEA and that they might benefit from more sports-specific nutrition education.

Return to Sport, Re-injury and Performance After the Anterior Cruciate Ligament Reconstruction: Evaluating the Role of International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) Scoring Systems.

Introduction Anterior cruciate ligament (ACL) tears are common injuries that can considerably impact an individual's quality of life and athletic performance. In these cases, surgical reconstruction of the ligament can be considered to restore stability to the knee. This study aims to investigate the time taken for individuals to return to sport post-ACL reconstruction, assess the rate of re-injuryand evaluate the reliability of the International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) scoring systems in predicting a return to sport at the pre-injury level. Methods In this retrospective study, a total of 104 patients who underwent ACL reconstruction between January 2016 and December 2022 by one surgical team at Mater Dei Hospital, Malta were evaluated using a self-administered questionnaire. The questionnaire was based on different components including the sport practised at the time of injury, sport engagement classification, return to sport, the ability to return to pre-injury levels of performanceand re-injury. The participants then had to fill in IKDC and KOOS evaluation forms. Results In this study, 73% (n=76) of individuals successfully returned to sport after ACL reconstruction, with no significant difference being found between professional and recreational athletes (Chi-squared=0.00455, p=0.95). After reconstruction, 31.7% (n=33) of participants experienced an ipsilateral or contralateral ACL tear, with those returning to sport within six months showing a fivefold increase in re-injury risk compared to individuals who returned at eight or 12 months, suggesting a significant association between return duration and re-injury. The relationship between scoring systems and return to sport at the pre-injury level of performance was analysed using binary logistic regression, revealing that achieving scores of 85.6 or higher in IKDC or 89 or higher in KOOS meant having a 95% probability of returning to sport at the pre-injury level. Conclusions By considering these scoring systems with other post-operative criteria, clinicians can offer a more customised rehabilitation plan tailored to each patient who undergoes ACL reconstruction.

Mediation Effect of Skill Levels in Relationship Between Degree of Participation and Injury Experience on Leisure Sports Participants : Based on Ball Sports with the Highest Injury Rate

PURPOSE This study aimed to prove the mediator effect of skill level on participation frequency and injury level of leisure sports players with the highest injury rate.METHODS Raw data of the “2019 Sports Safety accident data” conducted by the Korea Sports Safety Foundation were used for this study. We analyzed 857 leisure sports players participating in events with the top four highest injury rates (Basketball, Soccer, Baseball/Softball, Foot Volleyball). Frequency, descriptive statistics, and correlation analyses using SPSS version 27.0 and Process macro model 4 were employed for analysis.RESULTS The results regarding participation frequency, injury severity, and skill level among recreational athletes are as follows. First, a positive correlation was established between the participation frequency of recreational athletes and their skill levels. Second, the correlation between participation frequency and injury severity was observed only in soccer and basketball. Third, skill level plays a mediating role in the relationship between participation frequency and injury level. The results indicate that as the participation frequency among leisure sports players who participate in ball sports with a high injury rate increases, this affects the degree of injury.CONCLUSIONS Skill level appears to play a mediating role in the relationship between participation frequency and injury level. Based on the results, we recommend safety education not only on the relationship between participation frequency and injury level, but also the intermediary role of skill level.

Effects of an integrative warm-up method on the range of motion, core stability, and quality of squat performance of young adults.

This research aims to determine the effects of an integrative warm-up method on the range of motion in joints of the lower extremities, the strength of the stabilizer trunk muscles, and the quality of the basic movement patterns in older adolescents. The study sample consisted of 88 male students (age 20.1 ± 0.5). They were randomly divided into four groups: one control group (CG) (n = 17; 180.8 ± 7.9 cm; 82.3 ± 8.3 kg) and three experimental groups (EG): EG1 (n = 23; 180.9 ± 7.0 cm; 78.5 ± 9.5 kg), EG2 (n = 31; 182.2 cm ± 7.3 cm; 79.5 ± 11.5 kg), and EG3 (n = 17; 183.3 ± 4.9 cm; 77.5 ± 11.8 kg). The participants were subjected to a 6-week experimental treatment: EG1 once, EG2 twice, and EG3 three times a week. The experimental treatment consisted of four sub-phases representing the integrative warm-up Method: 1) Inhibition (self-myofascial release using a foam roller); 2) Lengthening (Static stretching in a maximum range of motion position); 3) Activation (Positional isometrics muscle activation of the trunk and gluteus); 4) Integration (Integrated all the previous phases into one complex movement pattern). Based on the covariance analysis (ANCOVA), statistically significant treatment effects were observed and positive changes were determined in all experimental groups. The differences between groups were observed in the following variables: Overhead Squat Assessment (p = 0.000; ), range of motion of left hip flexion (p = 0.000; ), range of motion of right hip flexion (p = 0.000; ) and range of motion of right hip extension (p = 0.051; ), Double Leg Lowering Test (F = 2.411; p = 0.014; ) and range of combined motion (plantar and dorsiflexion) of left ankle joint (p = 0.000; ). There was no significant difference in the Plank Test (F = 1.007; p = 1.007; ), range of combined motion (plantar and dorsiflexion) of right ankle joint (p = 0.088; ) and range of motion of left hip extension (p = 0.158; ). The participants of CG statistically significantly differed from EG1, EG2, and EG3 in the squat performance after the applied treatment. The effect of the treatment was the occurrence of a transformational processes in almost all measured variables. It can be concluded that the integrative method is effective and applicable in practice for both young adults and recreational athletes.

Timelines for Return to Different Sports Types After Eight Cervical Spine Fractures in Recreational and Elite Athletes: A Survey of the Association for Collaborative Spine Research.

Prospective cross-sectional survey. To identify timelines for when athletes may be considered safe to return to varying athletic activities after sustaining cervical spine fractures. While acute management and detection of cervical spine fractures have been areas of comprehensive investigation, insight into timelines for when athletes may return to different athletic activities after sustaining such fractures is limited. A web-based survey was administered to members of the Association for Collaborative Spine Research that consisted of surgeon demographic information and questions asking when athletes (recreational vs elite) with one of 8 cervical fractures would be allowed to return to play noncontact, contact, and collision sports treated nonoperatively or operatively. The third part queried whether the decision to return to sports was influenced by the type of fixation or the presence of radiculopathy. Thirty-three responses were included for analysis. For all 8 cervical spine fractures treated nonoperatively and operatively, significantly longer times to return to sports for athletes playing contact or collision sports compared with recreational and elite athletes playing noncontact sports, respectively (P< 0.05), were felt to be more appropriate. Comparing collision sports with contact sports for recreational and elite athletes, similar times for return to sports for nearly all fractures treated nonoperatively or operatively were noted. In the setting of associated radiculopathy, the most common responses for safe return to play were "when only motor deficits resolve completely" and "when both motor and sensory deficits resolve completely." In this survey of spine surgeons from the Association for Collaborative Spine Research, reasonable timeframes for return to play for athletes with 8 different cervical spine fractures treated nonoperatively or operatively varied based on fracture subtype and level of sporting physicality.

Hope for success as a mediator between Big Five personality traits and achievement goal orientation among high performance and recreational athletes.

The main objective of this study was to determine whether hope for success mediates the relationship between personality and goal orientation in high performance and recreational athletes. The cross-sectional study included 289 high performance and recreational athletes of various sports (age: M = 20.34, SD = 1.86). To examine personality, we used the Big Five IPIP-BFM-20 questionnaire. To assess hope for success, we used the Hope for Success Questionnaire. The Task and Ego Orientation in Sport Questionnaire (TEOSQ) was employed to examine goal orientation. Hope for success significantly mediates the relationships between conscientiousness, extraversion, emotional stability, intellect, and task goal orientation in sport. Higher levels of these personality traits are related to athletes' higher hope for success, which, in turn, is positively related to their task orientation. Personality traits may underpin the hope for success that develops from childhood. This, in turn, appears to be an important component on which, combined with the positive interaction and support from coaches, a task goal orientation beneficial to sport can be shaped in athletes.

Cross-education Effects of Wrist Flexor Strengthening on Grip Strength: Comparison of Eccentric and Concentric Training

Introduction: Time away from training and competition from sport injuries may lead to detrimental effects on muscle strength and endurance. The cross-education effect plays an important role in preserving strength during recovery and rehabilitation; however, the effects have been found to be inconclusive. In addition, the distinct impacts of eccentric and concentric strengthening exercises need to be explored. The objective of this study was to compare the cross-education effects of eccentric and concentric wrist flexor strengthening exercises on hand grip strength among recreational athletes. Methods: A total of 39 recreational athletes aged between 18-25 years old were randomly assigned into two groups of wrist flexor strengthening exercise: eccentric (ECC) and concentric (CON) training groups. The training period for the study was 4 weeks with 3 sessions of strengthening exercises per week. Handgrip strength was measured bilaterally, before and after the intervention using the JAMAR handgrip dynamometer. Results: Significant increases in hand grip strength were observed for the ECC and CON groups in both the trained and untrained hands following 4 weeks of training. However, the handgrip strength between the two groups in the untrained hand was not significantly different (p=0.64). The strength gain in the untrained hand was 9.8% and 10.8%, for ECC and CON groups, respectively. Conclusion: The cross-education effect was significant in improving strength in the untrained hand. There was no difference in strength gains between concentric and eccentric strength training.

Functional outcomes and rates of return to sport activities in a non-athlete population after the open Brostrom-Gould repair: a seven-year follow-up.

After an ankle sprain, up to 20% of patients may develop chronic lateral ankle instability (CLAI) requiring surgical treatment. The objective of this study was to investigate the functional outcomes and rates of return to sport activities in a cohort of non-athlete patients with chronic lateral ankle instability (CLAI) who underwent the opened Brostrom-Gould technique (BGT). Seventy-nine patients (seventy-nine feet) from three different centers undergoing BGT were reviewed. For clinical and functional analysis, the AOFAS ankle-hindfoot scale was applied and rates of return to sport activities were assessed. Correlation of Δ-AOFAS and rates of return to sport activities with all variables analyzed was performed. Mean AOFAS score improved from 64.6 to 97.2 (p < 0.001). Sixty-one (77.2%) returned to preinjury activities and 18 (22.8%) changed to a lower-level modality. Symptoms of instability were related to Δ-AOFAS (p = 0.020). Change in the sport activity was related to pain and symptoms of instability (p = 0.41 and p < 0.001). Recreational athlete patients who underwent the BGT demonstrated excellent functional outcomes after a mean follow-up of 7years. Residual pain and symptoms of instability after surgery were the main complaints associated with limitations in physical activities.

Pre-exercise hot water immersion increased circulatory heat shock proteins but did not alter muscle damage markers or endurance capacity after eccentric exercise

ABSTRACT Pre-exercise passive heating attenuates muscle damage caused by eccentric exercise in rats where the induction of heat shock proteins (HSPs) confers a myoprotective effect. We investigated whether pre-exercise hot water immersion (HWI) confers similar benefits in humans. Eleven recreational male athletes were immersed in 41°C water up to 60 min or until rectal temperatures reached 39.5°C. After a 6 h rest, the participants performed an eccentric downhill run for 1 h at −4% gradient to induce muscle damage. An endurance capacity test at 75% VO2max was conducted 18 h later. The control trial was similar except that participants were immersed at 34°C. Blood samples were collected to assess HSPs levels, creatine kinase, and lactate dehydrogenase activities. Plasma eHSP70 was higher post-immersion in HWI trials (1.3 ± 0.4 vs 1.1 ± 0.4; p = 0.005). Plasma eHSP27 was higher before (p = 0.049) and after (p = 0.015) endurance test in HWI. Leukocytic p-HSP27 was increased 18 h after HWI (0.97 ± 0.14 vs 0.67 ± 0.11; p = 0.04). Creatine kinase and lactate dehydrogenase activities were increased by 3-fold and 1.5-fold, respectively, after endurance test in HWI but did not differ across trials (p > 0.05). Mean heart rates were higher during eccentric run and endurance test in HWI as compared to control (p < 0.05). Endurance capacity was similar between trials (57.3 ± 11.5 min vs 55.0 ± 13.5 min; p = 0.564). Pre-exercise heating increased the expression of plasma eHSPs and leukocytic p-HSP27 but did not reduce muscle damage nor enhance endurance capacity.

Localized hamstring bioimpedance in marathon runners is related to muscle high-energy enzyme serum levels and predicts race time.

Introduction: The aim was to analyze the response of serum levels of inflammatory, high-energy muscle biomarkers and hamstring localized bioimpedance (L-BIA) measurements to marathon running and to ascertain whether they correlate with each other or with race time. Methods: Blood samples and hamstrings tetra-polar L-BIA measurements from 14 Caucasian male recreational athletes at the Barcelona Marathon 2019 were collected at base line, immediately after and 48 h post-race. Serum C reactive protein (sCRP), creatinine kinase (sCK) and lactate dehydrogenase (sLDH) were determined using an AU-5800 chemistry analyzer. L-BIA was obtained at 50 kHz with a Quantum V Segmental phase-sensitive bioimpedance analyzer. Results: Median sCRP increased (4-fold) after 48 h post-race. Median sCK and sLDH levels increased immediately post-race (3-fold, 2-fold) and 48h post-race (5-fold, 1-fold). Left, right and combined hamstring reactance (Xc) and phase angle (PhA) increased immediately post-race. Xc combined hamstring pre- and immediately post-race correlated with race-time and with sCK and sLDH median levels pre-race. Xc combined hamstring pre- and immediately post-race > 15.6 Ω and 15.8 Ω, respectively, predicted the race time of 3:00:00 h. Conclusion: L-BIA reactance (Xc) is an objective direct, real time, easy, noninvasive bioelectrical parameter that may predict muscle and marathon athlete performance.

The effects of acute self-myofascial release and various stretching techniques on selected physical fitness parameters in recreational athletes

The effects of acute self-myofascial release and various stretching techniques on selected physical fitness parameters in recreational athletes

Evaluation of the Kinesio Taping and Real-Time External Feedback Effects on Lower Extremity Function During Single-Leg Squat in Individuals With Tibiofemoral Varus Alignment

Background and Aims People with postural malalignment such as tibiofemoral varus (TFRV) may experience movement patterns dysfunction during functional activities that are related to non-contact lower extremity injuries. Training protocols should be designed for these people to control and improve their functional dysfunctions. The present study aimed to investigate the effect of posterior X-taping (PXT) and real-time external feedback (RTF) on kinematic and electromyographic indices of the lower extremities during the single-leg squat task in individuals with TFRV. Methods Electromyographic and kinematic information of the lower extremities of 24 recreational athletes with TFRV (PXT=12, RTF=12) were recorded while participants in both groups performed single-leg squat 5 times consecutively and took a 2-minute rest between two different conditions (before and after the intervention). To analyze the data, 2-way analysis of variance and Bonferroni post hoc test were used at the significant level of P≤0.05. Results The present study results indicated an increase in gluteus medius muscle activity (P=0.013) in the eccentric phase and a decrease in hip adduction (P=0.001) in maximal knee flexion (P=0.034) after the intervention compared to before the intervention in the RTF group. Also, there was a reduction in external tibiofemoral rotation of the knee after the intervention compared to before intervention in maximal knee flexion (P=0.034), eccentric phase (P=0.001), and concentric phase (P=0.001) in the PXT group. In addition, there was a decreased ankle pronation after the intervention compared to before the intervention in the eccentric phase (P=0.001) and concentric (P=0.001) in the PXT group and in the eccentric phase (P=0.004) in the RTF group. Besides, there was an increased ankle abduction after the intervention compared to before the intervention in the concentric phase (P=0.001), eccentric phase (P=0.001), and maximum knee flexion (P=0.004) in the PXT group, and in the eccentric phase in the RTF group (P=0.006). Finally, there was a decrease in ankle flexion dorsiflexion at maximum knee flexion after the intervention compared to before the intervention (P=0.017) in the RTF group. Conclusion The results of the present study showed that PXT and RTF interventions can affect the kinematic parameters of individuals with TFRV malalignment in different ways and can be used to correct immediately postural defects during the single-leg squat task.

Jumping towards field-based ground reaction force estimation and assessment with OpenCap

Low-cost and field-viable methods that can simultaneously assess external kinetics and kinematics are necessary to enhance field-based biomechanical monitoring. The aim of this study was to determine the accuracy and usability of ground reaction force (GRF) profiles estimated from segmental kinematics, measured with OpenCap (a low-cost markerless motion-capture system), during common jumping movements. Full-body segmental kinematics were recorded for fifteen recreational athletes performing countermovement, squat, bilateral drop, and unilateral drop jumps, and used to estimate vertical GRFs with a mechanics-based method. Eleven distinct performance-, fatigue-, or injury-related GRF variables were then validated against a gold-standard force platform. Across jumping movements, a total of six and three GRF variables were estimated with a bias or limits of agreement <5 % respectively. Bias and limits of agreement were between 5 and 15 % for seventeen and nineteen variables respectively. Moreover, we show that estimated force variables with a bias <15 % can adequately assess the within-athlete changes in GRF variables between jumping conditions (arm swing or leg dominance). These findings indicate that using a low-cost and field-viable markerless motion capture system (OpenCap) to estimate and assess GRF profiles during common jumping movements is approaching acceptable limits of accuracy. The presented method can be used to monitor force variables of interest and examine underlying segmental kinematics. This application is a jump towards researchers and sports practitioners performing biomechanical monitoring of jumping efficiently, regularly, and extensively in field settings.

Influence of altered torsional stiffness through sole modification of air pressure shoes on lower extremity biomechanical behaviour during side-step cutting maneuvers.

Directional changes in cutting maneuvers are critical in sports, where shoe torsional stiffness (STS) is an important factor. Shoes are designed based on different constructions and movement patterns. Hence, it is unclear how adjustable spacers into the sole constructions of air pressure chambers (APC) affect the STS in side-step cutting. Therefore, this study investigated the effects of altered STS through adjustable sole spacers on ground reaction force (GRF) and ankle and knee joint moments in side-step cutting. Seventeen healthy recreational athletes performed side-step cutting with experimental conditions including (i) barefoot (BF), (ii) unaltered shoes (UAS): soles consisting of APC, and (iii) altered shoes (AS): modified UAS by inserting elastomeric spacers into cavities formed by APC. Mechanical and biomechanical variables were measured. Significant differences were revealed across shoe conditions for impact peak (p = 0.009) and impulse (p = 0.018) in vertical GRF, time to achieve peak braking (p = 0.004), and peak propulsion (p = 0.025) for anterior-posterior GRF in ANOVA test. No significant differences were observed in GRF peaks and impulses between UAS and AS except for a trend of differences in impact peak (p = 0.087) for vertical GRF. At the ankle and knee joint, peak ankle power absorption (p = 0.019), peak knee internal rotation moment (p = 0.042), peak knee extension moment (p = 0.001), peak knee flexion moment (0.000), peak knee power absorption (p = 0.047) showed significant difference across three shoe conditions. However, no significant differences between the UAS and AS were noticed for peak joint moments and power. Altered shoe torsional stiffness did not significantly affect the peak forces and peak ankle and knee joint moments or powers; hence sole adjustment did not influence the cutting performance. This study might be insightful in sports footwear design, and adjusting shoe torsional stiffness by sole modification might be advantageous for athletes playing sports with cutting maneuvers to reduce the risk of injuries by controlling the twisting force at the ankle that frequently happens during cutting maneuvers.

The Effect of Acute Physical Fatigue on Information Processing, Pain Threshold and Muscular Performance

This study explores the multifaceted effects of acute physical fatigue on information processing, pain threshold, and muscular performance. Enrolling 28 recreational athletes, we used a high-intensity interval training (HIIT) protocol to induce fatigue and conducted pre- and post-intervention assessments. Our findings revealed significant physiological and performance adaptations following the HIIT sessions. Key observations included increased heart rate and rate of perceived exertion and an enhancement in horizontal jump performance and isometric hand strength but no significant change in cognitive processing speed. Remarkably, participants demonstrated a notable increase in pain threshold and blood lactate levels post-exercise. These results challenge traditional views of fatigue, indicating not only a physiological but also a psychological resilience to high-intensity stress. This study provides new insights into the complex interplay between physical fatigue, cognitive function, and pain perception, highlighting the comprehensive effects of HIIT on both physiological and psychological dimensions of human performance.

Bilateral movement asymmetries exist in recreational athletes during a 45° sidestep cut post-anterior cruciate ligament reconstruction.

Individuals post-ACL reconstruction (ACLR) are at elevated risk for ACL re-injury. While several studies have examined biomechanical asymmetries post-ACLR during landing, less is known about asymmetries during a sidestep cut. Therefore, the purpose of this study was to compare sagittal and frontal plane biomechanics at the hip and knee during a 45° sidestep cut in post-ACLR participants and healthy controls. Nineteen athletes post-ACLR and nineteen healthy controls performed a bilateral 45° sidestep cut while three-dimensional kinematics and kinetics were measured. Sagittal and frontal plane kinematics and kinetics were examined at the hip and knee during stance phase. A linear mixed model compared biomechanical differences between the limbs of ACLR and healthy control participants (α = 0.05). In the post-ACLR group, peak hip extension, peak knee flexion, sagittal hip and knee excursion, and the peak knee extensor moment were significantly lower in the ACLR surgical limb compared to the non-surgical limb (p < 0.05). The peak knee flexion angle and peak knee extensor moment were also lower in the ACLR surgical limb compared to the matched control limb (p < 0.05). In summary, post-ACLR participants exhibited altered sagittal plane movement in their surgical limb that was not demonstrated in the non-surgical limb or in control participants, which may suggest avoidance, or reduced utilization of the ACLR limb.

Investigating the impact of external load on muscle synergies during bipedal squats

PurposeA broad functional movement repertoire is crucial for engaging in physical activity and reducing the risk of injury, both of which are central aspects of lifelong health. As a fundamental exercise in both recreational and rehabilitative training regimes, the bipedal squat (SQBp) incorporates many everyday movement patterns. Crucially, SQBp can only be considered functional if the practitioner can meet the coordinative demands. Many factors affect coordinative aspects of an exercise, most notably external load. Since compound movements are assumed to be organized in a synergistic manner, we employed muscle synergy analysis to examine differences in muscle synergy properties between various external load levels during SQBp.MethodsTen healthy male recreational athletes were enrolled in the present study. Each participant performed three sets of ten SQBp on a smith machine at three submaximal load levels (50%, 62.5%, and 75% of 3 repetition maximum) across three non-consecutive days. Muscle activity was recorded from 12 prime movers of SQBp by way of electromyography (EMG). Muscle synergies were analyzed in terms of temporal activation patterns, i.e., waveform, as well as the relative input of each muscle into individual synergies, i.e., weight contribution.ResultsWaveforms of muscle synergies did not differ between loads. Weight contributions showed significant differences between load levels, albeit only for the gastrocnemius muscle in a single synergy.ConclusionTaken together, our results imply mostly stable spatiotemporal composition of muscle activity during SQBp, underlining the importance of technical competence during compound movement performance in athletic and rehabilitative settings.