Background Although subjects with forward head/rounded shoulders posture (FHRSP) may exhibit changes in scapular position and periscapular muscle strength relative to normal subjects, few studies have investigated this. Objective We compared scapular position and periscapular muscle strength between subjects with and without FHRSP. Methods In total, 50 subjects with FHRSP and 50 normal subjects were included. The craniovertebral angle (CVA) and rounded shoulder angle (RSA) were measured to determine FHRSP. To compare scapular position, scapular protraction, elevation, upward rotation, and anterior tilt were measured. To compare periscapular muscle strength, the strengths of the upper trapezius, middle trapezius, lower trapezius, and serratus anterior were measured using an isometric hand-held dynamometer. Results Relative to normal subjects, those with FHRSP had elevated, protracted, and anteriorly tilted scapulae and significantly weaker middle trapezius, lower trapezius, and serratus anterior (p<0.05). Both CVA and RSA showed negative correlations with protraction, anterior tilt of the scapula; they showed moderate positive correlations with scapular elevation. The strengths of the middle trapezius, lower trapezius, and serratus anterior muscles were moderately correlated with CVA and RSA (p<0.05). Conclusions Relative to normal subjects, those with FHRSP exhibited changes in scapular position and periscapular muscle deficits. This information will be useful for designing exercise programs for individuals with FHRSP.

Multimodal exercise programs do not specifically target lumbar paraspinal musculature, but incorporate aspects of different exercises to have an overall benefit. To investigate the effect of a multimodal exercise program on paraspinal muscle volume and composition, and patient outcomes in individuals with chronic low back pain (CLBP). Thirty-four participants with CLBP either completed a 14-week high-intensity training program (n = 8) including cardiorespiratory and resistance exercises 3 sessions per week or were waitlisted (n = 26). Participants underwent magnetic resonance imaging at baseline and post-intervention to assess paraspinal muscle volume (cm3) and fatty infiltration (% FI) at L3-L4, L4-L5, and L5-S1. Pain, disability, quality of life, pain-related fear (catastrophizing and Kinesiophobia), and anxiety were assessed via validated self-reported questionnaires. Mixed-design ANOVA revealed no significant time × group interactions for paraspinal muscle volume and %FI. An exploratory analysis revealed a significant increase in multifidus %FI in the control group at L3-L4, L4-L5, and L5-S1, with a concomitant increase in multifidus volume at L3-L4 and L5-S1. The exercise group had a significant increase in multifidus %FI and volume at L5-S1. Significant time × group interactions for pain, disability, catastrophizing and kinesiophobia, and a main effect of group in physical and mental health were found. Significant correlations were found between changes in patient-reported and functional outcomes with paraspinal muscle morphology. Multimodal exercise programs may help prevent LBP-related paraspinal muscle atrophy and %FI, and lead to concomitant improvements in pain, disability and pain-related fear in individuals with CLBP.

Objective This study investigates the effects of quadriceps isometric contraction training (QICT) on the symptoms, postural control, and movement ability of elderly women with knee osteoarthritis (KOA). Methods Forty-two older women with KOA were randomly divided into an experimental group (n = 21) and a control group (n = 21). All participants received the same health education for 16 weeks. The experimental group underwent QICT five times per week (contraction and relaxation for 5 s each, 30 repetitions per set, 10 sets, with a 30-s rest between sets). Assessments of KOA symptoms, postural control, and movement ability were performed at baseline and after the 16-week intervention. Results 1) At the 16th week compared to baseline: The experimental group showed a 27.1% reduction in pain, a 13.8% reduction in stiffness, and a 15.7% reduction in functional impairment scores. The body sway index on a firm surface with eyes closed decreased by 14.3%. The knee extension peak torque at 180°/s increased by 31.6%, and the angle difference in the knee flexion proprioception test (30°) decreased by 24.5%. The 6MWT distance increased by 11.9%, and the time for the TUG decreased by 12.9% (P < 0.05). 2) At the 16th week, group comparisons showed that the experimental group had significantly lower pain scores, body sway index on a firm surface with eyes closed, and angle difference in the knee flexion proprioception test (30°) (P < 0.05), and significantly higher knee extension peak torque at 180°/s and 6MWT distance compared to the control group (P < 0.05). Conclusion Quadriceps isometric contraction training can significantly improve pain, stiffness, functional impairment, static balance ability, knee extension strength, and 6-min walk distance in older women with KOA, as well as enhance knee flexion proprioception. These results indicate that 16-week QICT is a safe and economical non-pharmacological intervention that can effectively improve the clinical symptoms and functional status of older women with KOA, providing a feasible treatment option for community and outpatient rehabilitation. Notably, the 31.6% increase in knee extensor peak torque (180°/s) exceeds the MCID (20%) for older adults with KOA, reflecting significant clinical benefits.

Background Football is a sport that requires both aerobic and anaerobic performance with dynamic movements. Lower extremity injuries are common, especially in the ankle and foot, where foot pronation is a frequent biomechanical issue that can impair balance and performance. Objectives This study aimed to evaluate the effects of foot core exercises and arch-supported insoles on balance and vertical jump performance in elite football players. Methods Thirty elite male football players with foot pronation deformity were randomly assigned to two groups: Insole Group (IG, n = 15), using only arch-supported insoles, and Insole + Exercise Group (IEG, n = 15), combining insoles with structured foot core exercises for four weeks. Assessments included Navicular Drop Test (NDT), Y-Balance Test, Flamingo Balance Test, Vertical Jump Test, and Visual Analogue Scale (VAS). Pre- and pos t -test comparisons were analyzed using paired t -tests or Wilcoxon tests, and time × group effects were examined with repeated measures ANOVA. Results Significant improvements were observed in both groups for NDT, balance, and vertical jump performance ( p < 0.05). The IEG group showed superior gains in NDT and greater pain reduction. Additionally, vertical jump performance showed a near-significant trend favoring the IEG group ( p = 0.059). Conclusions Combining structured foot exercises with arch-supported insoles results in better outcomes for balance, pronation control, and jump performance compared to insoles alone. These findings support incorporating foot-specific exercises into rehabilitation for footballers with pronation. ClinicalTrials.gov NCT05821803 URL: https://clinicaltrials.gov/study/NCT05821803

Background While isokinetic knee strength profiles have been widely studied in athletes, data based on physical activity levels in young adult men and women remain limited. Objective This study aimed to determine knee isokinetic strength values according to physical activity level, with a focus on inactive (sedentary) individuals. Methods A total of 84 participants (42 females, 42 males) were divided three groups based on the International Physical Activity Questionnaire-Short Form (IPAQ-SF): inactive, minimally active, and active (12–15 per subgroup). Unilateral knee strength was assessed using isokinetic dynamometry at 60°/s and 180°/s. Two-way ANOVA was used to evaluate differences across groups, and gender comparisons were analysed using a t -test. Results Men demonstrated higher absolute strength values than women in all activity levels. In inactive and minimally active groups, there were no significant gender differences in extensor relative peak moment (PM/kg), peak work (PW/kg), or peak power (PPw/kg) ( p > 0.05). However, flexor values showed significant gender differences ( p < 0.05). In the active group, all relative strength values differed significantly between genders. Conclusion The absence of gender difference in extensor strength of inactive individuals suggests their use as a normative references for this cohort. Gender differences became more pronounced with increased physical activity.

Background It is unclear how back squat depth influences muscle activation and should be considered when designing strength training programs. Current evidence suggests this relationship is population-specific and should be examined in different populations to optimize strength training outcomes. This study examined the effect of different squat depths on muscle activation in college football players. Methods Sixteen Division II college football players performed back squat at three depths (C1 = 65°, C2 = 90°, and C3 = 115° knee flexion). During the descent and ascent phases, five-trial averages of mean gluteus maximus (GM), semitendinosus (ST), biceps femoris (BF), vastus medialis (VM), and vastus lateralis (VL) activation were calculated. Phase-specific differences were examined by calculating one-way repeated analyses of variance (α=0.05) and Bonferroni-corrected paired t-tests for post-hoc comparisons. Results Compared to C1, activation increased during C2 and C3 for the VM, VL, and BF during the descent and ascent phases. Additionally, during ascent, the greatest VM, VL, and BF activation occured during C3. Semitendinosus activation increased during C2 and C3 compared to C1 during the ascent phase, but it was not affected during the descent phase. Similarly, no GM activation changes were observed in either phase. Conclusions These findings indicate back squat depth influence on muscle activation is phase- and muscle-specific and should be considered when designing strength training programs for college football players.

BACKGROUND: The gluteus medius (GM) plays an important role in stabilizing the knee and preventing injury. OBJECTIVE: This study aimed to determine the immediate effects of weight-bearing gluteus medius exercises on lower-extremity muscle function and dynamic knee valgus. METHODS: Eighteen healthy adults (nine each of both sexes) performed three types of weight-bearing gluteus medius exercises (standing, mini-squat, and dead-lift), and a range of kinematic variables were tested in triplicate. Weight-supporting GM exercise consisted of three sets of 15 repetitions of the lateral band walk. The Y-balance test (YBT) and vertical single-leg jump were used as indicators of muscle function in the lower limbs. We used a video analyzer to film the dynamic knee valgus and performed a YBT for the supporting leg and landing leg following a jump. RESULTS: The height of the single-leg vertical jump and the posterolateral and total YBT scores were significantly higher in the dead-lift posture than in the standing and mini-squat postures. Motion analysis of the dead-lifts revealed high hip flexion on the supporting leg in the posterolateral direction, as determined by the YBT, with low levels of internal hip rotation on the landing leg during the one-leg vertical jump. CONCLUSION: As an immediate effect of gluteus medius exercise, the dead-lift posture facilitated single-leg vertical jump, posterolateral balance, and reduced dynamic knee valgus.

BACKGROUND: In short track speed skating, there is asymmetric fatigue of the gluteus maximus (GM) muscle resulting from the technique of skating. Scientific reports confirm the relationship between muscle fatigue and its change in the slope frequency of bioelectrical activity. OBJECTIVE: To investigate whether athletic experience in elite short track speed skating can distinguish the asymmetry change in slope frequency of the raw electromyographic signal (EMG) of the GM muscle, influenced by the disparity in experience between junior and senior athletes. METHODS: In the research, an elite group of short track speed skating national team athletes Junior and Senior, participated. Isometric tension GM muscle was tested using the Biering-Sorensen test. RESULTS: The study confirmed differences in the asymmetry of slope frequences EMG signal in GM muscle between juniors and seniors in short track speed skating ( p ⩽ 0.001). Senior athletes showed greater slope frequences in the right GM muscle ( p ⩽ 0.002), while juniors showed greater in the left GM muscle ( p ⩽ 0.008). Intergroup analysis revealed significantly meaningful differences ( p ⩽ 0.001) in the level of slope frequences of the right GM muscle (juniors vs. seniors), highlighting the asymmetry resulting from experience. CONCLUSIONS: Statistically significant differences in the level of slope frequences of the right gluteus maximus muscle juniors vs. seniors were demonstrated, suggesting asymmetry due to experience and skating technique.

BACKGROUND: Warm-up exercises are often recommended to enhance flexibility, reduce the risk of injury, and improve performance. However, the optimal number of warm-up repetitions remains unclear. Additionally, the previously suggested sit-and-reach test may not be suitable for efficiently stimulating the target muscles. OBJECTIVE: This study investigated the effects of a warm-up consisting of 15 straight leg raise (SLR) repetitions on hip and knee flexibility by comparing individuals with and without hamstring tightness (HT and NoHT, respectively). METHODS: Thirty healthy adults were classified as having HT or NoHT based on their SLR angle before warm-up. The participants performed 15 repetitions of the SLR as warm-up, followed by hip and knee flexibility tests. RESULTS: Warm-ups significantly improved hip and knee flexibility in both HT and NoHT groups. Improvements in flexibility were not significantly different between groups. The most notable increase in flexibility was observed between the sixth and ninth SLR trials. CONCLUSIONS: The clinical utility of a warm-up consisting of 15 SLR repetitions is supported by this study, as a substantial increase in hip flexibility was observed in all participants regardless of HT. In clinical settings, a maximum of 10 repetitions may be sufficient to achieve optimal results.

BACKGROUND: Maca extract may regulate oxidative stress and muscle damage after exhaustive endurance exercise (EEE); however, its impact on these physiological activities remains obscure. OBJECTIVE: To examine the effects of Maca extract supplementation on oxidative stress, muscle damage and aerobic capacity after EEE. METHODS: Twenty healthy men were assigned to Maca or placebo groups and received two doses per day for 12 weeks. Pre- and post-EEE tests assessed levels of oxidative stress and muscle damage. The EEE test also recorded metrics such as time to exhaustion, peak oxygen consumption, and maximal and average heart rates. RESULTS: Post-exercise, there was no significant difference in oxidative stress markers between the Maca and placebo groups. However, the Maca group exhibited lower stress levels at both Post-4 and Post-24 in comparison to Post-0, while the placebo group only displayed a decrease at Post-4. Notably, Maca extract supplementation immediately increased catalase activity at Post-0. Though muscle damage markers did not significantly differ, the slope of CK elevation in the Maca group appeared lower than the Placebo group, suggesting Maca’s potential in preventing muscle damage. However, no differences were noted on aerobic capacity markers. CONCLUSIONS: Maca extract may have some beneficial effects on reducing oxidative stress and possibly muscle damage after EEE.