International journal of exercise science最新文献

The purpose of this study was to investigate whether the ballistic push-up (BPU) is responsive to post-activation performance enhancement (PAPE) after a bench press conditioning exercise using velocity-based repetition control. Additionally, we aimed to evaluate the effects of range of motion (ROM) conditions on subsequent BPU performance. In a randomized crossover design, 18 males performed two conditions (full ROM and self-selected partial ROM) of bench press at 80% of their 1RM until mean concentric velocity dropped 10%. Each participant performed two pre- and six post-test BPUs to assess the PAPE effect. Paired sample t-tests assessed bench press performance measures. Multiple two-way repeated measures ANOVAs assessed differences in flight time, impulse, and peak power for the pre- and post-test BPUs. No significant differences existed between ROM conditions for total repetitions, volume load, or peak velocity. Compared to partial ROM, full ROM showed greater displacement (0.42 ± 0.05 vs. 0.34 ± 0.05 m), work (331.99 ± 67.72 vs. 270.92 ± 61.42 J), and mean velocity (0.46 ± 0.09 vs. 0.44 ± 0.08 m/s). Neither bench press ROM condition enhanced the BPU and were detrimental in some cases. Several time points showed partial ROM (flight time: 2 min post, impulse: 12 min post, peak power: 12 min post) significantly greater than full ROM, possibly indicating less fatigue accumulation. The BPU may require a different stimulus or may not be practical for PAPE effects in college-aged males. Partial ROM can be an alternative that achieves similar peak velocities while requiring less overall work.

Electroencephalography (EEG) allows for the evaluation of real time changes in brain (electrocortical) activity during exercise. A few studies have examined changes in electrocortical activity using stationary cycling, but the findings have been mixed. Some of these studies have found increases in brain activity following exercise, while others have found decreases in brain activity following exercise. Hence, it is of importance to identify post-exercise changes in brain activity. Sixteen healthy, untrained subjects (8 males; 8 females) participated in the study. All 16 participants performed a graded exercise test (GXT) to volitional exhaustion on an upright cycle ergometer. Continuous EEG recordings were sampled before (PRE) and immediately following (IP) the GXT. Regions of interest were primarily the dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC), and left and right motor cortex (MC). In the DLPFC, a frontal asymmetry index was also identified. There was a statistically significant increase in theta power in the DLPFC, VLPFC, and left and right MC from PRE to IP (all p < 0.05). There was also a shift towards right hemisphere asymmetry at the IP time point in the DLPFC (p < 0.05). Finally, there was an increase in alpha power from PRE to IP in the right MC (p < 0.05). EEG could prove to be an important way to measure the effects of central fatigue on brain activity before and immediately following exercise.

Softball athletes require multiple fitness traits (e.g., strength, speed, power) and sport-specific skills (e.g., hitting, throwing) for success. Lower-body strength could underpin these qualities; this has received little analysis among high school female athletes. This research investigated correlations between absolute and relative lower-body strength with age, linear speed, lower-body power, and throwing and hitting velocity in high school girls softball athletes. Archival data collected from 34 high school girls softball players (age=14.91±1.00 years; height=1.66±0.07 m; body mass=63.21±9.59 kg) from a private strength and conditioning facility was analyzed. The data included: age, height, and body mass; 0-9.14 and 0-18.29 m sprint interval times; standing broad jump (SBJ) distance (lower-body power); batted ball exit (i.e., hitting) and throwing velocity; and absolute and relative three-repetition maximum (3RM) front squat and hexagonal bar deadlift (HBD). Pearson's correlations (p<0.05) derived relationships between absolute and relative strength with the fitness and sport-specific tests. The results indicated significant relationships between the 3RM HBD with age (r=0.389) and hitting velocity (r=0.418). The 3RM front squat related to the SBJ (r=0.422) and hitting velocity (r=0.457). Relative 3RM HBD correlated with the 0-18.29 m sprint interval (r=-0.349). These results suggested that a strength and conditioning program that improves the lower-body strength of high school girls softball players could contribute to faster sprinting speed, further horizontal jumps, and greater hitting velocity. The results from this study highlights the value of strength enhancement in high school girls softball athletes and provides support for strength and conditioning program provision for these individuals.

The Army Combat Fitness Test (ACFT) is used to evaluate the fitness level of potential Cadets for military readiness. The purpose of this study was to evaluate the effectiveness of the exercise training program implemented by an Army Reserve Officers' Training Corps (ROTC) program to gauge the performance metrics of the ACFT.

Methods: Twenty-six student Cadets of the ROTC at the University of Alabama at Birmingham (UAB) program participated in the study. Over an 8-month period, the ROTC Cadets trained on campus three days per week. Training was performed in a circuit training format and each participant cycled through each of the four training stations (Strength, Conditioning, Core, and Endurance) for 15 minutes each session (for a total training time of 60 minutes). Each Cadet had body mass and body composition assessed as well as each component of the ACFT [maximum dead lift (MDL), standing power throw (SPT), hand release push-up (HRP), sprint-drag-carry (SDC), leg tuck/plank (LTK/PLK), and 2-mile run (2MR)]. Each variable was evaluated at three time points (pre-, mid-, and post-training program).

Results: There was a significant difference in the 2MR score between time points [F(2,50) = 4.530, p = .016, η² = 0.153] with a significant difference between time point at pre- and post-training (p = .02). No other variables displayed a significant change: body mass (p = .741), body fat percentage (p = .238), MDL (p = .061), SPT (p = .308), HRP (p = .126), SDC (p = 0.132), LTK/PLK (p = 0.583).

Conclusion: The results of this study suggest that the short-term training program used improves 2MR, but not other components of the ACFT over the course of an academic year.

The effects of hypopressive exercise (HE) on dynamic balance have never been studied. We aimed to study the effects of a HE program on dynamic balance, posterior chain kinematics and expiratory peak flow on female competitive roller skaters over a 6-week training period. Twenty competitive female roller-skaters (13-22 years of age, SD 2.25) performed a 30-minute HE session once weekly before the regular roller-skating practice for 6 weeks. The HE program consisted of breathing and postural awareness exercises in addition to 5 basic HE poses performed three times each. Dynamic neuromuscular control was assessed with the Y-Balance Test (YBT), posterior back chain kinematics with the sit and reach test and peak expiratory flow rate with a digital spirometer. Paired t-test revealed significant differences between the measurement periods for all YBT leg directions and composite score (p ≤ 0.01). Significant differences were also revealed between baseline and after the intervention for the sit and reach test (p ≤ 0.01) and peak expiratory flow (p = 0.01). No differences in forced expiratory volume in the first second were found (p = 0.04). These preliminary findings suggest that a 6-week HE program could be a feasible neuromuscular option for training dynamic balance, posterior back chain kinematics and peak expiratory flow in female roller-skaters.

Softball is a sport that requires speed, agility, and lower-body power to be successful. Accordingly, strength and conditioning programs have focused on improving speed and lower-body power, which are beneficial to players performing softball-related tasks. The purpose of this study was to determine the correlation between absolute and relative lower-body strength to performance measures among female collegiate softball players. Archived data collected during pre-season performance testing for twenty-one (n = 21) NCAA Division II collegiate softball players was used for this analysis. Measurements included countermovement jump (CMJ), broad jump (BJ), linear speed (LS), 505 test for change of direction speed (COD), and shuttle runs. Absolute lower body strength (ALBS) was measured using a 3-repetition maximum hex-bar deadlift (HBDL) and body weight was used to calculate relative lower body strength (RLBS) of each player. Pearson's correlation coefficients were used to relate measures of lower body strength to each performance test. Significant (p ≤ 0.05) large to moderate correlations were discovered between RLBS and COD (505L: r = -0.59, 505R: r = -.63), 300 yard (yd) shuttle run time (trial 1: r = -0.47, trial 2: -0.50), and lower-body power (CMJ: r = 0.48, BJ: r = 0.52). ALBS was correlated only to the BJ (r = 0.43). The results suggest that relative strength is related more with COD, shuttle run, and lower-body power when compared to absolute strength. Therefore, strength and conditioning professionals should consider measures of RLBS when administering softball specific tests for developing and implementing a successful strength program in collegiate softball.

No study has assessed supramaximal (over 100% 1RM) back squat variations as a potentiating stimulus in collegiate throwers. The purpose of this study was to test the hypothesis that a supramaximal Anderson (bottom-up) quarter squat potentiating stimulus would improve discus throw performance in Division I throwers compared to a dynamic warm-up alone. Nine NCAA division I thrower athletes (age: 20.1±1.4 years; 1RM back squat/body weight: 2.5±0.4 kg) randomly completed two sessions separated by at least 72 hours. One session involved a standardized dynamic warm-up alone (DyWU) followed by three trials of maximal discus throwing. The other session involved a dynamic warm-up with a supramaximal (105% 1RM) Anderson (bottom-up) quarter-squat set of 5 repetitions post activation performance enhancement stimulus (DyWU+PAPE) followed by three trials of maximal discus throwing. A two-way (warm-up strategy x time) ANOVA with repeated measures for each time point was used, with significance set at p< 0.05. There were no significant (p> 0.05) differences between DyWU alone versus DyWU+PAPE stimulus for discus throw distances at either 8 min. (31.7±5.6 vs 30.6±6.5 meters, respectively; d = -0.18), 11 min. (33.4±3.6 vs 31.3±4.7 meters, respectively; d = -0.52), or 14 min. post warm-up (34.1±3.9 vs 32.3±5.3 meters, respectively; d = -0.40). Compared to a dynamic warm-up alone, supramaximal Anderson quarter-squats following a dynamic warm-up had trivial/small to moderate detrimental effects on discus throw performance between 8-14 minutes post stimuli in Division I trained throwers, likely due to excess fatigue/PAPE inhibition.

The purpose of this meta-analysis was to quantify the difference in physical activity and sleep estimates assessed via 1) movement, 2) heart rate (HR), or 3) the combination of movement and HR (MOVE+HR) compared to criterion indicators of the outcomes. Searches in four electronic databases were executed September 21-24 of 2021. Weighted mean was calculated from standardized group-level estimates of mean percent error (MPE) and mean absolute percent error (MAPE) of the proxy signal compared to the criterion measurement method for physical activity, HR, or sleep. Standardized mean difference (SMD) effect sizes between the proxy and criterion estimates were calculated for each study across all outcomes, and meta-regression analyses were conducted. Two-One-Sided-Tests method were conducted to metaanalytically evaluate the equivalence of the proxy and criterion. Thirty-nine studies (physical activity k = 29 and sleep k = 10) were identified for data extraction. Sample size weighted means for MPE were -38.0%, 7.8%, -1.4%, and -0.6% for physical activity movement only, HR only, MOVE+HR, and sleep MOVE+HR, respectively. Sample size weighted means for MAPE were 41.4%, 32.6%, 13.3%, and 10.8% for physical activity movement only, HR only, MOVE+HR, and sleep MOVE+HR, respectively. Few estimates were statistically equivalent at a SMD of 0.8. Estimates of physical activity from MOVE+HR were not statistically significantly different from estimates based on movement or HR only. For sleep, included studies based their estimates solely on the combination of MOVE+HR, so it was impossible to determine if the combination produced significantly different estimates than either method alone.

The COVID-19 pandemic affected many aspects of everyday life including school, fitness regimens, and social interactions. The purpose of this study is to understand how COVID-19 restrictions affect the cardiovascular and mental health of Doctor of Physical Therapy (DPT) students as they progressed through the program. Data collection occurred in 16 DPT students (8F:8M, 24±3 years) over a total of 3 visits from 2020 to 2022, during high, moderate, and low COVID-19 restrictions. Outcome measures included VO2max, Venous Occlusion Plethysmography (VOP), %fat mass measured via DEXA, Perceived Stress Scale (PSS) and International Physical Activity Questionnaire (IPAQ). A RM-ANOVA with pairwise comparisons was utilized. Significance was set prior at an α level of 0.05. There was a significant increase (p<0.05) from visit 1 to 2 in VO2max, VOP baseline, BMI, and METs. There was a significant decrease (p<0.05) from visit 2 to 3 in VO2max. Finally, a significant increase in visit 3 was seen from visit 2 in VOP peak. Overall, there was no significant difference observed for PSS and %fat mass (p>0.05). Between high and moderate restrictions, there was an increase in VO2max, VOP baseline, and METs. However, between moderate and low restrictions, only VOP Peak increased. This could be attributed to gyms being closed and limiting the type of physical activity a person could do to exercises like running or walking. When restrictions were lifted, traveling to and from classes, traveling to gyms, and socializing all increased, limiting the time for physical activity.

High levels of fat-free mass (FFM) are favorable for athletes and are related to sport performance. However, fat-free mass index (FFMI), which includes adjustments for height, may offer a better way to characterize FFM beyond raw values. As FFMI is understudied relative to sport, the purpose of the current study was to assess position and age group differences in FFMI among collegiate American football players. National Collegiate Athletic Association DIII (n=111) football players underwent body composition assessment via bioelectrical impedance analysis. FFMI was calculated by dividing FFM by height squared. One-way analyses of variance with Bonferroni post-hoc tests were conducted to evaluate differences in FFMI by position and age groups (α<0.05). The overall mean FFMI was 23.50 ± 2.04 kg · m^-2, with values ranging from 18.1-27.7 kg · m^-2. FFMI was highest in linemen (24.8 ± 1.5 kg · m^-2) and lowest in specialty players (20.6 ± 1.4 kg · m^-2) (p<0.05). No differences in FFMI were apparent across age groups (p>0.05). Current findings demonstrate that an athlete's upper limit for FFMI may exceed 25 kg · m^-2, and differences exist across positions, likely due to position-specific demands. These measurements serve as a foundation for tailoring nutritional and exercise plans, forecasting athletic performance, and supplying coaches with standardized data about the potential for additional FFM accretion in collegiate American football players.