Research Quarterly for Exercise and Sport最新文献

Purpose: The purposes of this study were to determine the moderation effects of affective attitude on the effects of cognitive attitude and intention on leisure-time moderate-to-vigorous physical activity (MVPA). Methods: A total of 2100 undergraduate students completed validated instruments measuring their affective and cognitive attitude, intention to do MVPA, and leisure-time MVPA. Hierarchical regression analyses and Hayes' Process program (model 1 and model 58) were used to address the research questions. Results: The results showed that affective attitude significantly moderated the effects of cognitive attitude on MVPA. It suggested that when affective attitude was negative, the effect of cognitive attitude on MVPA was not significant; when it was positive, the higher the value of affective attitude score, the larger the effects of cognitive attitude on MVPA. The results also showed that affective attitude significantly moderated the effect of intention on MVPA and the indirect effects of cognitive attitude on MVPA through intention. It suggested that the higher the value of the affective attitude, the larger the effects of intention on MVPA and the larger the indirect effects of cognitive attitude on MVPA through intention. Conclusions:These results indicate that the moderating role of affective attitude in behavior change is important and should be considered for future theory development on the relationship between attitude and behavior. Practically, it suggests that people's affective attitude should be first understood and addressed when designing PA promotion programs.

Purpose: To 1) examine whether blood flow restriction would provide an additional exercise-induced hypoalgesic response at an upper and lower limb when it is incorporated with low-load resistance exercise until failure, and 2) examine if increases in blood pressure and discomfort, with blood flow restricted exercise, would mediate the exercise-induced hypoalgesia over exercise without blood flow restriction. Methods: Forty healthy young participants completed two trials: four sets of unilateral knee extension exercise to failure at 30% of one-repetition maximum, with and without blood flow restriction. Pressure pain thresholds were assessed before (twice) and 5-min post exercise at an upper and lower limb. Blood pressure and discomfort ratings were recorded to examine mediating effects on exercise-induced hypoalgesia with blood flow restricted exercise. Results: Pressure pain threshold increased following both exercise conditions compared to a control, without any differences between exercise conditions at the upper (exercise conditions vs. control: ~0.37 kg/cm²) and lower (exercise conditions vs. control: ~0.60 kg/cm²) limb. The total number of repetitions was lower for exercise with blood flow restriction compared to exercise alone [median difference (95% credible interval) of -27.0 (-29.8, -24.4) repetitions]. There were no mediating effects of changes in blood pressure, nor changes in discomfort, for the changes in pressure pain threshold at either the upper or lower limb. Conclusion: The addition of blood flow restriction to low-load exercise induces a similar hypoalgesic response to that of non-blood flow restricted exercise, with a fewer number of repetitions.

Purpose: This study aimed to verify whether there are differences in physical, technical, and tactical assessment outcomes derived from field-based tests and small-sided games (SSG) in addition to anthropometric and maturational characteristics between players classified as promising and less promising as per the coaches' perception. Method: A total of 53 male U-15 youth soccer players (age: 14.8 ± 0.2 years, weight: 61.7 ± 6.9 kg, height: 171.8 ± 6.7 cm) and three experienced coaches from three distinct sports clubs were enrolled in this study. Based on the coaches' perception, players were split into three group levels for both short- and long-term success ranking: (i) promising (PL; top 5 players; n = 15), (ii) intermediate (IL; n = 23) and (iii) less promising (LPL; 5 bottom players; n = 15). The following measures were determined: anthropometry, maturity offset, vertical jump, and aerobic-anaerobic running performance, soccer- specific skills tests, GPS-based running metrics, technical and tactical actions during SSG, and minutes played throughout the season. Results: There were no differences between groups for anthropometrical, maturational, and physical outcomes. PL players in both rankings covered more distances at sprinting and presented more offensive technical and tactical actions during SSG than their LPL peers. PL and IL presented more minutes played in competitive seasons than LPL of short-term ranking. Conclusion: The biggest differences between the players ranked by their coaches were apparent only during a representative game task, emphasizing the importance of SSG as a tool to assess the players' technical-tactical awareness. In addition to the SSG, the coach's eye plays a key role during the talent identification and selection process.

Purpose: The highest work-rate that provides maximal oxygen uptake ($\dot{V}{O}_{2max}$) may be one of the best exercise stimuli to yield both $\dot{V}{O_2}_{max}$ and lactate accumulation. The aim of this study was to analyze physiological and metabolic acute responses of an exercise modality performed at the upper boundary of the severe exercise domain, and compare those responses with exercise modalities applied within the severe exercise domain. Method: Ten trained male cyclists participated in this study. The $\dot{V}{O}_{2max}$, corresponding power output (PO_VO2max), and the highest work-rate that provides the $\dot{V}{O}_{2max}$ (I_HIGH) were determined by constant work-rate exercises. Cyclists performed three high-intensity interval training (HIIT) strategies as follows; HIIT-1: 4-6 × 3-min at 95% of PO_VO2max with 1:1 (workout/rest ratio); HIIT-2: 16-18 × 1-min at 105% of PO_VO2max with 1:1; HIIT-3: 4-7 × 1-2-min at the I_HIGH with 1:2. Capillary blood samples were analyzed before, immediately after HIIT sessions, and at the first, third, and fifth minutes of recovery periods. Lactate difference between the highest lactate response and resting status was considered as the peak lactate response for each HIIT modality. Results: Time spent at $\dot{V}{O}_{2max}$ was greater at HIIT-1 and HIIT-3 (272 ± 127 and 208 ± 111 seconds, respectively; p = 0.155; effect size = 0.43) when compared to the HIIT-2 (~26 seconds; p < 0.001), while there was a greater lactate accumulation at HIIT-3 (~16 mmol·L^-1) when compared to HIIT-1 and HIIT-2 (12 and 14 mmol·L^-1, respectively; p < 0.001). Conclusions: In conclusion, HIIT-3 performed at I_HIGH was successful to provide time spent at $\dot{V}{O}_{2max}$ with a greater lactate accumulation in a single session.

Purpose: The muscle oxygen uptake ($m\dot{V}{O}_2$) kinetics following exercise, measured by near-infrared spectroscopy, has been used as a functional evaluation of muscle oxidative metabolism. This study aimed to determine the $m\dot{V}{O}_2$ off-kinetics and verify the relationship of the recovery rate of $m\dot{V}{O}_2$ (k) with time-trial performance and different aerobic parameters in trained rowers. Methods: Eleven male rowers (age: 20 ± 3 years; $\dot{V}{O}_{2}max$: 4.28 ± 0.35 L·min^-1) used a rowing ergometer to perform (I) an incremental test to determine the maximal oxygen uptake ($\dot{V}{O}_{2}max$) and peak power output (P_peak); (II) several visits to determine maximal lactate steady state (MLSS); and (III) a 2000-m rowing ergometer performance test. Also, one test to determine $m\dot{V}{O}_2$ off-kinetics of the vastus lateralis muscle using a repeated arterial occlusions protocol. Results: The $m\dot{V}{O}_2$ generated a good monoexponential fit (R² = 0.960 ± 0.030; SEE = 0.041 ± 0.018%.s^-1). The k of $m\dot{V}{O}_2$ (2.06 ± 0.58 min^-1) was associated with relative $\dot{V}{O}_{2}max$ (r = 0.79), power output at MLSS (r = 0.76), and P_peak (r = 0.83); however, it was not related with 2000-m rowing performance (r = -0.38 to 0.52; p > .152). Conclusion: These findings suggest that although not associated with rowing performance, the $m\dot{V}{O}_2$ off-kinetics determined after a submaximal isometric knee extension may be a practical and less-exhaustive approach than invasive responses and incremental tests to assess the muscle oxidative metabolism during a training program.

Purpose: We investigated the effect of drop-set (DS) and rest-pause (RP) systems compared to traditional (TRAD) resistance training on muscular adaptations and psychophysiological responses. Methods: Twenty-seven trained men (age: 23.4 ± 3.4 years; resistance training experience: 5.1 ± 1.7 years) were assigned to experimental groups (DS: n = 9, 3 × 10 repetitions at 75% with 6 additional repetitions at 55% 1RM; RP: n = 9, 3 × 16 repetitions at 75% 1RM; TRAD: n = 9, 4 × 12 repetitions at 70% 1RM) and performed lower-limb training sessions twice a week for 8 weeks. Maximum dynamic strength (1RM) and localized muscular endurance (LME) tests were performed in 45° leg press at baseline and post intervention. Session-RPE was assessed 15 min after the end of each training session. Results: A significant time vs. group interaction was observed for 1RM (p = .012) and LME (p < .0001). Post hoc comparisons revealed that RP elicited greater gains in muscular strength than DS (p = .044) but not TRAD (p = .116); and DS elicited greater LME than RP (p < .001) and TRAD (p = .001). No statistical differences were observed in Session-RPE and training strain between conditions; however, RP promoted higher training monotony (p = .036) than DS and TRAD. Conclusions: The DS and RP systems have a potential role in training programs aiming to promote muscle strength and localized muscular endurance adaptations, respectively. However, RP may promote higher training monotony than DS and TRAD, even though the other psychophysiological responses are similar.

Purpose: This study analyzed the acute mechanical response to three workouts of the day (WOD) protocols in as many repetitions as possible (AMRAP), every minute on the minute (EMOM), and for time (FT) models by quantifying the degree of mechanical fatigue induced by popular resistance exercises in the Cross modalities, front squat (FS), and shoulder press (SP). We also analyzed whether the exercises' fastest velocity (Vfastest) could be an objective indicator of relative intensity (%1RM). Methods: Nine trained men performed three FS and SP exercises protocols. The degree of fatigue was quantified by the velocity loss (VL) achieved in both exercises and the velocity loss achieved in the WOD (VL_WOD). Results: The VL_WOD in the AMRAP, EMOM, and FT protocols was 73.2 ± 10.9%, 61.6 ± 15.1%, and 76.1 ± 8.8%, respectively. In the AMRAP and FT protocol, the V_fastest showed very strong relationships with the %1RM for FS and SP (r = -0.83, -0.75, respectively, p < .01); while in the EMOM protocol, there was a strong relationship between these variables, only for the SP (r = -0.61, p < .05). In the FT protocol, we observed an extremely strong relationship for FS (r = -0.91, p < .001) and very strong (r = -0.71, p < .05) for SP between these variables. Conclusion: Therefore, the AMRAP and FT training models induce the highest degrees of mechanical fatigue in the FS and SP exercises, and the V_fastest is a reliable tool for estimating relative intensity in resistance exercises of Cross modalities.

Objective: The aim of the current study was to evaluate the physiological and metabolic responses to running with whole-body electromyostimulation (wbEMS) compared to running without electromyostimulation (control, CG). Methods: Twenty healthy participants (9 male/11 female, age 42 ±7 years) conducted an incremental step test with respiratory gas analysis until exhaustion. Trials were conducted as wbEMS and CG in a random order. As outcome measures, (A) objective total exhaustion, (B) athletic responses (max. time and velocity) and (C) physiological and metabolic responses (V'O₂/ kg, V'E, EE, RER, lactate) were compared. (D) The impact on the skeletal muscle was assessed prior, 48 h & 72 h after trial. Results: During both trials, participants (A) ran until total exhaustion. Nonetheless, (B) time and velocity till exhaustion as well as (C) RER prior to the first lactate threshold and V'E were reduced with wbEMS. All other correlates did not differ significantly between wbEMS and CG. Following 48 h and 72 h after the trial with wbEMS, (D) the impact on the skeletal muscle was 7- to 9-fold higher compared to baseline values. Values differed significantly to those after running without wbEMS. Conclusion: With the additional stimulation during voluntary activation, wbEMS induces earlier fatigue and a shift in energy metabolism toward fat utilization. Even during aerobic endurance tasks, a great impact on the skeletal muscle indicated by the rise in CK could be observed which promotes wbEMS as an alternative training stimulus that is easy-to-apply and effective during endurance training.

Public health guidelines for resistance training emphasize a minimal effective dose intending for individuals to engage in these behaviors long term. However, few studies have adequately examined the longitudinal time-course of strength adaptations to resistance training. Purpose: The aim of this study was to examine the time-course of strength development from minimal-dose resistance training in a large sample through retrospective training records from a private international exercise company. Methods: Data were available for analysis from 14,690 participants (60% female; aged 48 ± 11 years) having undergone minimal-dose resistance training (1x/week, single sets to momentary failure of six exercises) up to 352 weeks (~6.8 years) in length. Linear-log growth models examined strength development over time allowing random intercepts and slopes by participant. Results: All models demonstrated a robust linear-log relationship with the first derivatives (i.e., changes in strength with time) trending asymptotically such that by ~1-2 years strength had practically reached a "plateau." Sex, bodyweight, and age had minimal interaction effects. However, substantial strength gains were apparent; approximately ~30-50% gains over the first year reaching ~50-60% of baseline 6 years later. Conclusion: It is unclear if the "plateau" can be overcome through alternative approaches, or whether over the long-term strength gains differ. Considering this, our results support public health recommendations for minimal-dose resistance training for strength adaptations in adults.

Purpose: With the increased access to neural networks trained to estimate body segments from images and videos, this study assessed the validity of some of these networks in enabling the assessment of body position on the bicycle. Methods: Fourteen cyclists pedaled stationarily in one session on their own bicycles while video was recorded from their sagittal plane. Reflective markers attached to key bony landmarks were used to manually digitize joint angles at two positions of the crank (3 o'clock and 6 o'clock) extracted from the videos (Reference method). These angles were compared to measurements taken from videos generated by two deep learning-based approaches designed to automatically estimate human joints (Microsoft Research Asia-MSRA and OpenPose). Results: Mean bias for OpenPose ranged between 0.03° and 1.81°, while the MSRA method presented errors between 2.29° and 12.15°. Correlation coefficients were stronger for OpenPose than for the MSRA method in relation to the Reference method for the torso (r = 0.94 vs. 0.92), hip (r = 0.69 vs. 0.60), knee (r = 0.80 vs. 0.71), and ankle (r = 0.23 vs. 0.20). Conclusion: OpenPose presented better accuracy than the MSRA method in determining body position on the bicycle, but both methods seem comparable in assessing implications from changes in bicycle configuration.