International journal of exercise science最新文献

To investigate the effects of differing treadmills on impact acceleration and muscle activation.

Methods: 15 males and 7 females (27.8 ± 7.7yrs), engaged in two sessions of high-incline walking (HIW), and low-incline jogging (LIJ) on different deck systems (cushioned) treadmills (TM1 and TM2). Sessions lasted 5-minutes, and participants maintained a self-selected pace matched for each session. EMG markers were placed over the Tibialis Anterior (TA), Soleus (SOL), Lateral Gastrocnemius (LG), Biceps Femoris (BF), Gluteus Maximus (GM), Anterior Deltoid (AD), Vastus Lateralis (VL), and the Erector Spinae (ES). Trident Inertial Measurement Units (IMU) were attached to the foot and sacrum. EMG activity, impact accelerations, heart rate, and RPE were collected at the 4-minute 30-seconds mark.

Results: Peak EMG was higher for LG (p = 0.005), SOL (p = 0.010), and BF (p < 0.001) on TM1 compared to TM2, while AD exhibited lower peak activation during HIW compared to LIJ on TM2 (p = 0.010). The integral EMG activity increased for AD, ES, VL, SOL, LG, and GM only during HIW for both TM1 and TM2. However, only integral EMG activation of BF and LG differed between TM1 and TM2 during HIW. Foot and sacrum resultant acceleration was notably lower during HIW compared to LIJ on both TM1 and TM2. HR was significantly higher on TM1 (171.2 ± 24.8bpm) compared to TM2 (164.62 ± 23.7 bpm, p < .05) during HIW (p < .001), and RPE also differed between TM1 (13.96 ± 1.96) and TM2 (13.09 ± 1.97) during HIW (p < .05).

Conclusion: At the same speed (correspond to an RPE of 11) and grade, treadmill design may impact peak and integral muscle EMG patterns, RPE, and HR responses.

This investigation evaluated validity and reliability of the HUMAC360 linear position transducer (LPT) compared to the Tendo Sport Weightlifting Analyzer (TENDO) for measuring mean velocity (MV), peak velocity (PV), and displacement (D) during the bench press. Seventeen recreationally active individuals completed three visits. During visit one, participants were assessed for their one repetition maximum (1RM) bench press. During subsequent visits, participants completed two sets of three repetitions of bench press at 30, 50, 60, and 70% 1RM. The HUMAC and TENDO measured MV, PV, and D simultaneously, while the HUMAC also measured repetition duration (T). Validity of the HUMAC and inter-set and inter-day reliability for MV, PV, D, and T were assessed using Intraclass Correlation Coefficients (ICCs). The HUMAC demonstrated limited validity when compared to the TENDO as ICCs ranged from poor to good across all measurements. Significant differences were observed between devices for MV, PV, and D at all intensities (p < 0.001). Inter-set reliability was excellent for all intensities and measurements, but inter-day reliability was impaired for MV, PV, and D at higher intensities. Validity of the HUMAC for measuring MV, PV, and D is limited when compared to TENDO. As the HUMAC reliably assesses MV, PV, D, and T, both inter-set and interday (up to 60% 1RM), it may serve as an autoregulatory tool for velocity-based training.

The purpose of this study was to compare changes in circulating microRNAs -126 (c-miR-126) and -222 (c-miR-222) following acute serial concurrent exercise (SCE) and integrated concurrent exercise (ICE) sessions among young, sedentary adults. Ten males and 9 females completed the study procedures. For SCE, participants performed resistance exercise (RE) followed by aerobic exercise (AE), without mixing the two. For ICE, participants performed a brief bout of AE before each set of RE. Blood was collected before, immediately after (IP), and 1 h (1HR) after each exercise session. Expression of c-miR-126 significantly increased from baseline at IP (1.6-fold SCE, 2.1-fold ICE; p = .037) and 1HR (1.8-fold SCE, 1.7-fold ICE; p = .034) following both sessions, with no difference between the two sessions. Expression of c-miR-222 significantly increased from baseline at IP (1.7-fold SCE, 1.9-fold ICE; p = .024) and 1HR (2.0-fold SCE, 1.6-fold ICE; p = .038) following both sessions, with no difference between the two sessions. There were no differences in peak heart rate or average heart rate between the two workout sessions. Both SCE and ICE patterns appear equally effective at acutely increasing c-miR-126 and -222.

Gravel cycling is a relatively new cycling discipline, with the Union Cycliste Internationale (UCI) hosting their first World Championships in 2022. Gravel races combine features of road racing, cyclocross, and mountain biking, including terrain of varying technical difficulty, long distances, substantial elevation gain, obstacles, and limited opportunities to stop for in-race nutrition. This study assessed hydration responses to gravel races of three different distances. Data were collected on saliva osmolarity (SOsm), body mass (BM), fluid intake, and nutrition knowledge at a gravel cycling race in April 2023. A total of 121 participants completed pre-race surveys, 53 provided pre-race measures of BM and SOsm, and 38 participants completed post-race testing. Only 22.6% (n = 12) of participants were hydrated before the race, with 56.6% mildly dehydrated (n = 30), 18.9% moderately dehydrated (n = 10), and 1.9% severely dehydrated (n = 1). Post-race, 15% (n=6) were still hydrated, 20% (n = 8) were mildly dehydrated, 47.5% (n = 19) were moderately dehydrated, and 17.5% (n = 7) were severely dehydrated. Analyses revealed significant decreases in BM and increases in SOsm from pre- to post-exercise in the two longer race distances (p < 0.05). There was a significant effect of race distance on energy, fluid, carbohydrate, and sodium intake (p < 0.05). Sweat rates were not different (p > 0.05). Our results revealed an effect of race distance on BM losses, SOsm, and energy, fluid, carbohydrate, and sodium intakes. Future studies could inform optimal feeding and hydration strategies.

The purpose of the study was to compare heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) following high load resistance exercise (HLRE) and blood flow restriction exercise (BFRE) with a knee wrap (kBFRE) and pneumatic cuff (pBFRE). Eleven men (N = 9) and women (N = 2) participated. HR, SBP, and DBP were collected at Rest, immediately post exercise (IP), 10-, 30-, and 45-minutes post exercise. Repeated measures ANOVAs assessed the effects of condition across time on all variables. Significant effects were examined with pairwise comparisons and a Sidak correction. Significance was defined a priori p ≤ 0.05. There were significant condition by time interactions for HR (p = 0.005; ES = 0.31), SBP (p = 0.016; ES = 0.27), and DBP (p = 0.03; ES = 0.24). There were significant main effects of time for HR (p < 0.001; ES = 0.78), SBP (p < 0.001; ES = 0.84), and DBP (p = 0.004; ES = 0.44). The HR was increased from Rest for up to 45 minutes across all conditions. IP, the HR was lower following pBFRE compared to HLRE. There was an increase in SBP at IP. SBP was higher following HLRE compared to kBFRE and pBFRE. DBP was decreased at 10 minutes across all conditions, with kBFRE prompting larger reductions compared to HLRE at 10 minutes. DBP was lower following kBFRE compared to pBFRE at 45 minutes. This study suggests that BFRE alters cardiovascular function differently than HLRE, but is dependent on cuff type. Specifically, pneumatic cuffs may attenuate the increase in the HR and SBP response, and knee wraps augment the reduction in DBP.

The high prevalence of obesity and physical inactivity in the U.S. is a public health crisis. This study aims to examine the effects of high-intensity functional training (HIFT) on exercise perceptions and physiological changes in inactive females. A pre-test and post-test, quasi-experimental design was conducted with inactive, middle-aged females (n = 8) participating in an 8-week supervised and verified intervention (2-week High-Intensity Interval Training, 6-weeks HIFT). The Health Belief Model Scale for Exercise (HBMS-E) survey was completed pre-intervention, post-intervention, and 4-week follow-up to assess exercise perceptions. Pre- and post-intervention physiological assessments included: body composition, strength (1-repetition maximum (RM) bench press (BP), 5-RM deadlift (DL), and maximal oxygen consumption (V̇O_2max). A within-subjects repeated-measures ANOVA assessed the HBM constructs between pre-intervention, post-intervention, and follow-up. Dependent t-tests compared physiological outcomes pre- to post-intervention. There was a significant decrease between pre-intervention, post-intervention, and follow-up for objective (F(2, 14)=22.24, p < .001) and subjective barriers (F(2, 14) = 11.20, p = .001), and a significant increase in self-efficacy (F(1.08, 7.53)= 8.96, p = .02). There was a significant increase in V̇O_2max (p = .001, d = 1.81), 1-RM BP (p < .001, d = 2.51), and 5-RM DL (p = .001, d = 1.83) pre- to post-intervention. Findings suggest HIFT positively influenced middle-aged females' perceptions of barriers and self-efficacy related to exercise and provides fitness benefits to improve health and wellness.

Resistance training at fast velocities is suggested to be more effective for improving muscular strength and movement speed compared to slow, heavy training. This study aimed to examine the effects of a fast-velocity (FVRT) compared to a slow-velocity (SVRT) resistance training program on maximal strength, maximal movement speed, and load-velocity characteristics in older adults. Nineteen community-dwelling older adults were randomly assigned to either the FVRT or SVRT group and completed a twice weekly, progressive resistance training protocol for 8-weeks. Both groups were instructed to move the weight "as fast as possible" during the concentric phase of the movement and received movement velocity biofeedback. Absolute (1RM_ABS) and relative (1RM_REL) strength, maximal movement speed (MMS), load velocity slope (LV_SLOPE) and the area under the LV_SLOPE (LV_AREA) were measured during a 1RM assessment at baseline (PRE), after 4-weeks (MID), and after 8-weeks (POST) of training. No differences were observed in average total volume between groups (FVRT: 47490.3±10888.3 kg/session; SVRT: 44679.3±15250.9 kg/session, p = 0.26, g = 0.60). Both groups improved absolute and relative strength and maximal movement speed. There were no interaction or main effects of LV_SLOPE for time. However, there was a main effect of LV_AREA for time. Both MID and POST LV_AREA were larger than PRE (MID posterior mean_diff: 0.24, 95% CI: 0.13-0.35; POST posterior mean_diff: 0.39, 95% CI: 0.27-0.49). These findings suggest both FVRT and SVRT can lead to improvements in strength and movement speed in older adults. The lack of significant changes in LV_SLOPE indicates that maximal strength and movement speed better reflect performance improvements in older adults than LV_SLOPE.

Visual processing is crucial for sports performance, influencing athletes' ability to interpret and respond to visual stimuli. This study investigated distinct visual processing patterns among Thai elite athletes in gymnastics, soccer, and esports, utilizing visual P300 event-related potentials (P300 ERPs). Forty-two female athletes (14 gymnasts, 14 soccer players, and 14 esports athletes) participated. Visual P300 ERP responses were stimulated using the visual oddball paradigm. One-way ANOVA was employed to assess significant differences among the groups in P300 ERPs data, including amplitude and latency of waveforms, response time, and accuracy rate. Significant differences were found across the groups in various parameters. Esports athletes exhibited longer P300 ERP latencies at the frontal electrode sites compared to gymnasts (p = 0.01), suggesting slower visual processing in the frontal brain regions. Gymnasts demonstrated the fastest response times, significantly quicker than esports and soccer players (p < 0.01). In contrast, soccer players exhibited the highest accuracy rate (p = 0.03). These findings underscore athletes' diverse visual processing strategies in different sports contexts, reflecting sport-specific adaptations. Understanding these distinct visual processing patterns can guide targeted interventions aimed at improving cognitive abilities and decision-making processes among elite athletes, ultimately contributing to better overall performance.

Neck pain is a widespread problem in society with many variables influencing its cause. The angle of the hip may influence the kinematics of the neck in addition to the myoelectrical activation of the surrounding musculature that contributes to the development of neck pain. The purpose of this study was to investigate the changes in spinal inclination angles and muscle activity in the neck using a 10 deg wedge in a forward slope, neutral and rear slope seated position. Forty subjects were recruited for this study. Each subject sat at a workstation under the 3 different sitting positions for ten minutes for each condition. During this time, the subjects typed a prompt for seven minutes and rested for the remaining 3 minutes. This was repeated for each position. Inclination angles and electromyography data were collected at different intervals during each trial. The results showed a significant difference in mean inclination angle among the three positions in the pain group (p<0.01). The head and neck inclination angles were higher in the rear sloped position compared to the forward slope (p<0.001). In the pain group, there was no significant change in the mean muscle activity in the UT in the forward slope as compared to the rear slope and neutral positions (p ≤0.01). The results of this study suggest that the forward sloped position provides a favorable body alignment compared to the other positions which may then lead to less unwanted muscle activation.

This study assessed the effect of an eight-minute cycling intervention using varying intensities on exercise-induced hypoalgesia (EIH). The main objective of this study was to examine the effect of varying intensities on pressure pain threshold (PPT) and heat pain threshold (HPT) at the thigh and forearm, tested pre- and post-cycling intervention. Healthy male participants (n = 16) performed a graded exercise test on a cycle ergometer to establish their peak power output (PPO). In subsequent visits, participants completed five different 8-minute cycling interventions, with intensities randomly assigned to one of three counterbalanced orders. HPT and PPT were applied to the thigh and forearm two times before and after each cycling intervention. Additionally, there was a notable effect of intensity on PPT in the thigh, with significant changes at intensities of 90% (p = 0.024) and 100% PPO (p = 0.003). In the forearm, repeated measures ANOVA indicated that there was no significant interaction or main effect for intensity and time. Similarly, for HPT, the analysis did not show significant interaction or main effects for both intensity and location. This study was the first to examine EIH using an 8-minute cycling intervention on a cycling ergometer at individualized intensities. Higher intensity cycling sessions generated EIH locally in the thigh using PPT. A short but high intensity cycling intervention may have clinical relevance, as it can provide an intervention to reduce localized pain immediately after exercise using a pressure pain stimulus.