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On Equal Footing? Sex-moderated Post-activation Performance Enhancement in Trained Individuals
No full textPost-activation performance enhancement (PAPE) is a phenomenon whereby performing one exercise improves performance of a subsequent physical activity. Despite widespread use of PAPE, there is a notable lack of research on the phenomenon in female athletes – a prevalent issue in exercise and sports science overall. Given the importance of jumping ability in various sports and considering potential sex differences in movement mechanics and determinants, understanding how to most effectively utilize PAPE may help inform performance approaches in all athletic populations. PURPOSE: The primary purpose of this study was to compare back squat PAPE effects on countermovement jumps (CMJs) in trained female and male individuals. A secondary aim was to compare such effects at different proximities to failure. METHODS: Participants completed 4 experimental sessions involving baseline CMJs followed by either passive rest (CON) or 2 sets of 1 (1R), 3 (3R), or 5 (5R) back squat repetitions at each participant’s 5RM weight, and subsequent CMJ testing at min. 3, 6, and 9. RESULTS: 15 females and 16 males successfully completed all sessions. Bayesian statistical analyses revealed sex-moderated posterior probabilities of positive change in jump height (JH) %difference [95%CrI] from baseline at 1R min. 9 (F=0.34 [0.12,0.54]; M=0.09 [0.0,0.19] and 3R min. 3 (F=0.47 [0.20,0.67]; M=0.11 [0.0,0.3] but not in 5R. 3R and 5R most effectively maintained JH and improved relative peak force and rate of force production for both sexes. CONCLUSION: Sex may moderate PAPE effects of heavy back squats performed far from failure but is unlikely to moderate such effects at close proximity to failure. PAPE is also more likely to be observed following heavy back squats performed closer to failure. While more research is needed directly comparing sex-moderated responses to different potentiation protocols, practitioners are advised to take higher-intensity approaches to PAPE for both females and males
Relationship Between Upper and Lower Quadrant Stability and Muscular Endurance in Active Law Enforcement Officers
No full textThe push-up test (PUT) is commonly used to assess muscular endurance (ME) in law enforcement officers (LEOs), as ME has been attributed to performance during many occupational tasks. Research has shown a relationship between upper-quadrant stability (UQS) and PUT, however the contribution of lower-quadrant stability (LQS) to PUT performance is less well understood. PURPOSE: The purpose of this study was to investigate the relationship between UQS, LQS, and PUT performance in active LEOs. METHODS: Twenty-two active male LEOs (40.5 ± 9.4 y, 178.5 ± 6.9 cm, 93.5 ± 11.7 kg) completed the upper quadrant Y-Balance test (UQYBT), lower quadrant Y-Balance test (LQYBT), and a maximal PUT. The UQYBT was performed in the push-up position, with the dominant (D) hand centered on a platform. Reach distances in the medial, superolateral, and inferolateral directions with the non-dominant (ND) hand were recorded. This was repeated with alternative arm positioning. The LQYBT was also performed bilaterally. Participants stood on one foot on the platform, hands on hips while reaching the other foot in three directions (anterior, posterior medial and posterior lateral). Composite scores for the UQYBT and LQYBT for the D limb (UBYBT-D and LQYBT-D, respectively) and ND limb (UBYBT-ND and LQYBT-ND, respectively) were determined and normalized to limb length. For the PUT, participants started in the standard position and full range of motion repetitions were counted (without rest) until form deterioration. Predictors of PUT scores were determined with a stepwise regression analysis using SPSS version 30 (IBM Corp) and an alpha significance of p \u3c 0.05. RESULTS: The average PUT score (28.41 ± 16.4) was above the 50th percentile compared to similar aged LEOs according to NYS Fitness Requirements. UQYBT-D scores were the only significant predictor in a model that explained 36.0% of the variance in PUT scores (R2 = 0.360, F[1,20] = 11.241, p = 0.003). CONCLUSION: The composite score for UQYBT-D was the lowest score when compared to UQYBT-ND, LQYBT-D, and LQYBT-ND, indicating that limitations in D arm stability may influence performance through the kinetic chain during whole body movements. The limited sample size and selection bias present during stepwise regression analysis warrants further testing with more participants to verify these findings
Effect of Short-term Beetroot Supplementation on High-intensity Cycling Sprint Performance in Recreationally Active Adults
No full textNitric Oxide (NO) has a plethora of physiological benefits including vascular smooth muscle relaxation and vasodilation. Beetroot (BR) is a rich source of dietary nitrate which serves as a precursor for enhancing the bioavailability of circulating NO levels. BR has been used by athletes as a supplement to potentially enhance blood flow and exercise performance. Understanding the performance effects of BR supplementation is important for determining its practical value as an ergogenic aid for athletes and active individuals.PURPOSE: This study aimed to investigate whether BR supplementation enhances exercise performance during a cycling sprint protocol. METHODS: Ten recreationally active males participated in this randomized, placebo-controlled, crossover study. Participants consumed 2 x 70 mL of either nitrate-rich BR (~400 mg nitrate; Beet It Sport®) or a nitrate-depleted placebo daily for three days preceding the experimental trials. An additional dose of 2 x 70 mL was ingested on the day of testing 2.5 hours before completing the cycling sprint protocol. Each participant completed a cycling sprint protocol consisting of 10 x 5-second sprints on a stationary bike interspersed with 55 seconds of rest between efforts. Average power, peak power, distance, and average speed were assessed during each sprint. A two-way repeated measures analysis of variance (2 x 10) was conducted to examine group differences in cycling performance, with statistical significance set at p \u3c 0.05. RESULTS: No significant differences were observed between the groups for cycle performance metrics (p \u3e 0.05). CONCLUSION: BR supplementation did not produce significant improvements in cycling performance measures in this study. This contrasts with previous findings indicating that acute nitrate supplementation can enhance power production during short cycling sprints. The variability in outcomes across studies highlight the need for further investigation into the conditions under which nitrate supplementation is most effective
Differential Associations Between Physical Activity Subtypes and Psychological Health in Sedentary Urban College Students
No full textCollege students often report high levels of stress and anxiety, which can negatively impact academic performance and overall well-being. Physical activity (PA) is widely recognized for its mental health benefits; however, PA encompasses various domains. Subtypes such as Leisure-Time Physical Activity (LTPA), Occupational Physical Activity (OPA), Transportation Physical Activity (TPA), and Domestic Physical Activity (DPA) may not yield the same psychological outcomes. Understanding how specific PA domains relate to mental health may offer insight into how daily routines influence psychological well-being in urban college students. PURPOSE: This study aimed to determine whether distinct types of PA are differentially associated with anxiety, stress, and cognitive function in sedentary urban college students. METHODS: Data were collected from baseline assessments for a 10-week intervention studying the effects of peer-led resistance and aerobic training on psychological health. Prior to the intervention, 55 sedentary students (mean age = 20.7 ± 2.6 years) completed the International Physical Activity Questionnaire (IPAQ) and self-reported psychological assessments using the NIH Toolbox and PROMIS scales. Pearson correlation analyses examined relationships between PA types, anxiety, stress, and cognitive function. RESULTS: Cognitive function was strongly negatively correlated with anxiety (r = -0.62; p \u3c 0.05) and perceived stress (r = -0.59; p \u3c 0.05). TPA energy expenditure predicted lower cognitive function (r = -0.29; p \u3c 0.05) and higher stress (r = 0.27; p \u3c 0.05). DPA (MET-minutes) was positively correlated with stress (p \u3c 0.05), but not with cognitive function or anxiety (p \u3e 0.05). LTPA and TPA energy expenditure were significantly correlated (r = 0.41; p \u3c 0.05). LTPA MET-minutes were positively correlated with anxiety (r = 0.49; p \u3c 0.05) and negatively with cognitive function (r = -0.31; p \u3c 0.05). CONCLUSION: Findings suggest that different PA domains are uniquely associated with anxiety, stress, and cognitive function, highlighting the importance of contextual factors in the relationship between PA and mental health
Difference in Knee Joint Structure and Lower Extremity Functioning Among People with Varying Severity of Knee Osteoarthritis: A Cross-Sectional Study
No full textInternational Journal of Exercise Science 18(5): 910-921, 2025. Osteoarthritis (OA) is a highly prevalent musculoskeletal condition. It is reported that knee OA progressively affects lower-extremity functioning. Evidence is lacking on when there is a substantial decline in function and whether this trend differs between males and females and disease severity. This study aimed to examine influence of gender and increasing grade of knee OA on lower-extremity function. Following Institutional Ethical Committee approval and signed-informed consent, 115 participants (57-males, 58-females), aged 40-65 years, with diagnosed knee OA (grade 1-4) were recruited. Lower-extremity function was studied using reliable and valid outcome variables such as muscle strength-endurance, joint motion, ground-level activity exposure and physical activity. The medial knee joint space width (JSW) decreased by 56.7%(males) and 49.2%(females) from grades 1 to 2 and by 29.6%(males) and 47.8%(females) from grades 3 to 4. Lower-extremity muscle strength and mobility measured by 30-second-deep-squat test declined by 62%(males) and 40.4%(females) from grades 1 to 2 and by 94.4%(males) and 60.9%(females) from grades 3 to 4. Lower-extremity muscle endurance measured by 30-second-chair-sit-to-stand test declined by 8.3%(males) and 7.1%(females) from grades 1 to 2 and by 31.6%(males) and 85.7%(females) from grades 3 to 4. Physical function decreased by 0.3%(males) and 2.3%(females) from grades 1 to 2 and by 22.7%(males) and 32.0%(females) from grades 3 to 4. Physical activity decreased by 27.6%(males) and 28.6%(females) from grades 1 to 2 and by 53.1%(males) and 60.7%(females) from grades 3 to 4. A substantial decline was observed from grades 3 to 4, when both males and females presented considerable reductions in lower-extremity function
AGE-RELATED DIFFERENCES IN THE ACUTE EFFECTS OF MUSCLE FATIGUE ON STABILITY
No full textPostural stability is necessary for maintaining body position, achieving coordination, and reducing fall risk. With advancing age, fall risk increases, due in part to a decreasing ability to maintain postural stability. Muscular fatigue, which results from activities of daily life or exercise, may further intensify instability and increase risk of falls. Some research indicates older individuals develop muscular fatigue sooner than younger adults, but less is known about the differences in the time to recover stability. PURPOSE: To compare the acute effects of muscular fatigue on stability and time to recover stability between older and younger adults. METHODS: Participants from two age groups (n = 30; younger, 18-28 y; and older, 55-65 y) will be recruited. Four participants, two per group, have completed the study. Limits of Stability (LOS) testing and a fatiguing protocol, comprised of sit-to-stand to volitional fatigue, were performed. LOS tests were conducted at baseline and 0, 5, 10, 15, and 20 minutes after the fatiguing protocol. The variables of interest from LOS include reaction time (RT) and maximum excursion (MXE). The effects of age and recovery time on RT and MXE were analyzed with a 2 (group) by 6 (time) ANCOVA, with time to fatigue as a covariate (α = .05). RESULTS: Preliminary analysis indicates that after adjusting for time to fatigue for MXE, there was no significant group by time interaction (p = .11), and no main effect of time (p = .07) or group (p = .07). For RT there was no significant interaction (p= .71) or main effect of time (p = .34), but there was a significant group effect (p = .002), with younger participants exhibiting faster reaction times (0.45 ± 0.14 s) compared to older participants (0.53 ± 0.11 s) on average. CONCLUSION: Based on these early results, balance measures were not significantly affected by fatigue. However, given the low sample size currently, these results may differ as additional data are collected. Between groups, there was no difference in maximum excursion based on age, which indicates that both groups were effective in reaching their limits of stability. There was a significant difference in reaction times between groups, with younger participants having faster reaction times at all testing points. This is to be expected with changes in the neuromuscular system that occur with age
PORTABLE LEG PRESS FOR CLOSED KINETIC CHAIN EXERCISES: ENHANCING STRENGTH FOR PATIENTS IN INTENSIVE CARE
No full textPatients in the intensive care unit (ICU) often experience severe muscle weakness and atrophy due to prolonged immobility, necessitating effective and unique rehabilitation strategies. PURPOSE: To evaluate the effectiveness of resisted closed kinetic chain (CKC) exercises compared to existing interventions in improving functional outcomes for patients with critical illness. METHODS: A comprehensive literature review was conducted using databases such as EBSCOhost, CINAHL, PubMed, TRIP, and MEDLINE. Key terms included intensive care unit, closed kinetic chain vs. open kinetic chain exercises, leg press machine, acute care, portable leg press, modalities, and functional outcomes. Studies were selected based on their relevance to interventions focused on combatting the effects of immobility and their impact on functional outcomes for patients in ICU. RESULTS: CKC exercises, which involve multiple joints and mimic functional activities, have shown superior functional outcomes compared to open kinetic chain (OKC) exercises. Implementing CKC exercises via a portable leg press can be done at bedside, making it feasible for patients in the ICU where out-of-bed mobility may be contraindicated. The studies reviewed indicate that CKC exercises improve balance, lower extremity muscle activation, and gait quality. A prototype portable leg press has been developed to facilitate these exercises, addressing the limitations of existing interventions like neuromuscular electrical stimulation (NMES), cycle ergometry, and tilt-tables. CONCLUSION: Resisted CKC exercises using a portable leg press offer a promising alternative to traditional strengthening modalities in the ICU. These exercises can enhance muscle strength, balance, and functional mobility, improving patient outcomes. Further research is needed to validate these findings and optimize the implementation of CKC exercises in critical care settings
