This study examined the effects of a 6-week intermittent exercise training, at different intensities, on body composition, functional walking and aerobic endurance in overweight children. Forty-eight overweight children (age: 10.4 ± 0.9 years) were randomly assigned to either intervention or control group. Lower and higher intensity intermittent exercise groups (LIIE and HIIE) performed intermittent running three times a week. LIIE performed more intervals at a lower intensity [16 intervals at 100% of individual maximal aerobic speed (MAS), 8 minutes in total], and HIIE performed fewer intervals at a higher intensity (12 intervals at 120% of MAS, 6 minutes in total). Each interval consisted of a 15-second run at the required speed, followed by a 15-second passive recovery. After 6 weeks, HIIE had a significantly (p < 0.05) higher percentage reduction in sum of skinfolds (i.e. calf and triceps), and significantly (p < 0.05) fewer steps during the functional obstacle performance, as compared with LIIE and control group. Significant improvement (p < 0.05) was found in intermittent aerobic endurance for HIIE as compared to the control group. Higher intensity intermittent training is an effective and time-efficient intervention for improving body composition, functional walking and aerobic endurance in overweight children.

Ho, IMK, Luk, JTC, Ngo, JK, and Wong, DP. Effects of different intraset rest durations on lifting performance and self-perceived exertion during bench press exercise. J Strength Cond Res 35(8): 2114–2120, 2021—This study compared the number of successful repetitions, failure rates, and ratings of perceived exertion (RPEs) among intraset rest (ISR) protocols (0-, 20-, or 40-second rest between third and fourth repetitions) during bench press exercise with total 3 sets and 6 repetitions per set at 6 repetition maximum (6RM) load. Thirty-four college-aged men performed 6RM loads with ISR 0, 20, and 40 on 3 separate visits in a counterbalanced order while the total rest time and duration of each protocol was equated. Results showed failure rates of 32.4% for ISR0 (11 subjects with failed repetition), 14.7% for ISR20, and 2.9% for ISR40. The ISR had a small positive effect on increasing successful repetitions in: second set, ISR40 vs. ISR0 and ISR20 vs. ISR0 (both +0.2 rep, d = 0.28); third set, ISR40 vs. ISR0 (+0.5 rep, d = 0.55) and ISR20 vs. ISR0 (+0.4 rep, d = 0.39); and total number of repetition: ISR40 vs. ISR0 (+0.7 rep, d = 0.46) and ISR20 vs. ISR0 (+0.5 rep, d = 0.36). The ISR also had small effect on decreasing RPE in: second set, ISR40 vs. ISR0 (−0.6, d = −0.21); third set, ISR40 vs. ISR0 (−0.7, d = −0.26); and average RPE of the 3 sets, ISR40 vs. ISR0 (−0.6, d = −0.24). The longer ISR could further decrease RPE only in the third set (ISR40 vs. ISR20: −0.6, d = −0.23, small effect). Strength coaches may use the ISR40 rest redistribution to reduce RPE and enhance repetition sustainability.

The use of RSA/RCOD index indicates the repeated change-of-direction (RCOD) performance relative to the repeated-sprint ability (RSA) and provides a standardized approach to prioritize training needs for RSA and RCOD. To compare the RSA/RCOD index among different age groups, RSA and RCOD were measured from 20 under-16 players (U16), 20 under-19 players (U19), and 17 first-team professional players (PRO) from a football (soccer) club that has regular participation in the UEFA Champions League. Each player performed the RSA and RCOD tests, during which the fastest time (FT), average time (AT), total time (TT), and percentage decrement score (%Dec) were recorded. No significant differences were found in RSA/RCOD index-FT, AT, TT, and %Dec among the 3 groups (p > 0.05) and between U19 and PRO in all RSA and RCOD measures (p > 0.05). Most values of RSA/RCOD index were 0.51 among the U16, U19, and PRO groups. Moreover, we concluded that the RSA/RCOD index might not be further changed after 16 years of age unless specific training programs for RSA and RCOD are prescribed. Therefore, this study provides an empirical case, and coaches can establish the RSA/RCOD index value relevant to their training system and monitor players' training needs of RSA and RCOD in a longer term.

Background: Street workout (SW) is an urban sport based on calisthenic exercises. Injury profiles and risk factors are widely explored in various sport disciplines. However, because of the lack of research in SW, injury profiles have not yet been established. Purpose: To investigate the characteristics and prevalence of injuries and variables that may increase these odds in SW practitioners. Study Design: Case-control study; Level of evidence, 4. Methods: An electronic survey was conducted between September 2018 and March 2019 in order to obtain practitioner information, physical activity level, training characteristics, and injury information of SW practitioners. Responses from 93 practitioners were eligible for analysis. Univariate and multivariate binary logistic regression analyses were used to examine the association among several variables and the presence of injury in the past 12 months based on odds ratios (ORs). Results: Overall, 62.4% of the 93 participants reported an injury in the previous 12 months, and tendinopathy was the most reported diagnosis (31.0% of injured practitioners). High injury frequency was reported in the shoulder (23.0%) and back (upper and mid) (18.4%). Overtraining was the most reported perception of cause of injury (56.9%). Most injured practitioners (20.7%) performed freestyle exercises before the injury, followed by upper body exercises. A history of previous injuries (OR, 4.078; P = .005) and the middle and higher tertiles of vigorous physical activity (OR, 4.370; P = .015 and OR, 5.634; P = .003, respectively) were associated with a higher odds of injury. Conclusion: In SW, the shoulder and back (upper and mid) were the most injured body parts, with tendinopathy being the most frequent diagnosis. Overtraining was typically reported as the perceived cause of injury, with freestyle and upper limb exercises the most performed exercises when injured. A history of previous injuries, along with vigorous physical activity, was found to augment the odds of injury. More research is needed to corroborate our findings, along with increased knowledge about SW practice and injuries.

This study compared the effects of eight-week tyre flipping training intervention using light and heavy tyres on physical fitness performance. Twenty-nine young physically active males were divided into light (n = 15) and heavy (n = 14) tyre flipping groups evenly according to body weight and height. Body-to-tyre weight ratios were 0.61 ± 0.06 for the light tyre (LTTG) and 1.51 ± 0.16 for the heavy tyre training (HTTG) groups. Fitness parameters were measured before and after the intervention. One-way ANCOVA analysis indicated no significant between-group differences when pre-test values were controlled. Both groups demonstrated within-group improvements in 6RM bench press (ES: 0.98 in LTTG and 1.10 in HTTG), intermittent endurance (ES: 0.45 in LTTG and 0.66 in HTTG), five horizontal jumps (ES: 0.35 in LTTG and 0.26 in HTTG), and agility (ES: 0.34 in LTTG and 0.41 in HTTG). Both groups improved tyre flipping efficiency, through decreasing average set duration and work-rest ratios in the first six training sessions, and reached a plateau starting from the 7th training session. This study provides the first empirical evidence for coaches to justify usage of tyre flip training and the timing to progressive overload for a population with limited weight training and no tyre flip training experience.