Uthoff, A, Oliver, J, Cronin, J, Harrison, C, and Winwood, P. Sprint-specific training in youth: Backward running vs. forward running training on speed and power measures in adolescent male athletes. J Strength Cond Res 34(4): 1113–1122, 2020—This study compared the effects of 2 sprint-specific training programs against the natural development of speed, power, and stiffness in a group of adolescent male athletes. Forty-three male adolescents (aged 13–15 years) were randomly assigned to 1 of 2 training groups; backward running training (BRT = 26), or forward running training (FRT = 17). A physical education class (n = 24) of similar age constituted a control (CON) group. Both training groups performed running sessions matched for distance and intensity biweekly for 8 weeks. Parametric and magnitude-based inferences were used to analyze within group (pre-post measures) and between group (gain scores) for 10-m, 10- to 20-m, and 20-m sprint times, vertical countermovement jump (CMJ) height, and vertical leg stiffness. Both running groups significantly improved (p ≤ 0.05) in all performance tests from pre-training to post-training, with effect sizes ranging from −1.25 to 0.63. When the groups were compared, the BRT and FRT groups improved significantly (p ≤ 0.01) on all sprint performances and stiffness relative to the CON group. The BRT group demonstrated favorable effects for 10-m and 20-m sprint performances (effect size [ES] = −0.47 and −0.26, respectively) and CMJ height (ES = 0.51) compared with the FRT group. These results demonstrate that forward and backward sprint-specific training programs enhance speed and power measures more than natural development in adolescent male athletes. Furthermore, the greater training responses in sprint performance and CMJ ability indicate that BRT is a useful tool for improving concentric strength and power and may be classified as a sprint-specific training method.

With striking force playing such a critical role in the success of full-contact combat sports such as mixed martial arts, taekwondo, and boxing, coaches and scientists must be able to track this performance metric accurately and reliably. This review will cover practitioner understanding of key kinetic variables used in the assessment of striking important concepts relating to the validity, reliability, and reporting of meaningful performance changes in the assessment process, a critique of the methods used to monitor changes in striking forces, and provide practical recommendations for practitioners in the field. This understanding will help coaches and scientists assess and interpret the effectiveness of training.

Bustos, A, Metral, G, Cronin, J, Uthoff, A, and Dolcetti, J. Effects of warming up with lower-body wearable resistance on physical performance measures in soccer players over an 8-week training cycle. J Strength Cond Res 34(5): 1220–1226, 2020—Warm-ups provide an opportune time to integrate specific movements to improve performance. This study aimed to examine the effects of adding wearable resistance (WR) lower-limb loading to a warm-up on physical performance measures in soccer athletes. Thirty-one national-level soccer players (aged 16–18 years) were matched for speed and allocated to either a WR training (WRT = 15) or an unloaded (CON = 16) group. Both groups performed the same warm-up 2–3x·wk⁻¹ for 8 weeks with the WRT group wearing 200- to 600-g loads on their calves. Pre-training, mid-training, and post-training data were collected for 10- and 20-m sprint times, repeated sprint ability, and vertical countermovement jump (CMJ) and horizontal countermovement jump (standing long jump [SLJ]) performance. Wearable resistance training improved pre-training to post-training 10- and 20-m sprint times more than the unloaded training (effect size [ES] = −1.06 to −0.96, respectively; 60.0–66.7 vs. 18.8–37.5% > smallest worthwhile change [SWC]). Both groups decreased CMJ over the first 4 weeks (ES ≥ 0.45) and increased CMJ performance over the second 4 weeks of training (ES ≥ 0.27). Both the WRT and CON groups improved SLJ performance after the 8-week training block (ES = 0.85 and 0.93, respectively; 86.7 and 62.5% > SWC, respectively), yet no differences were identified between groups. These findings indicate that 8 weeks (23 sessions) of WR training appears to elicit practically meaningful improvements in accelerated sprinting and horizontal jumping performance. Strength and conditioning practitioners should consider including WR in sports where sprinting and horizontal force production are critical performance indicators.

This study determined the acute changes in rotational work with thigh attached wearable resistance (WR) of 2% body mass during 50-m sprint-running. Fourteen athletes completed sprints with, and without, WR in a randomised order. Sprint times were measured via timing gates at 10-m and 50-m. Rotational kinematics were obtained over three phases (steps 1–2, 3–6 and 7–10) via inertial measurement unit attached to the left thigh. Quantification of thigh angular displacement and peak thigh angular velocity was subsequently derived to measure rotational work. The WR condition was found to increase sprint times at 10-m (1.4%, effect size [ES] 0.38, p 0.06) and 50-m (1.9%, ES 0.55, p 0.04). The WR condition resulted in trivial to small increases in angular displacement of the thigh during all phases (0.6–3.4%, ES 0.04–0.26, p 0.09–0.91). A significant decrease in angular velocity of the thigh was found in all step phases (−2.5% to −8.0%, ES 0.17–0.51, p < 0.001–0.04), except extension in step phase 1 with the WR. Rotational work was increased (9.8–18.8%, ES 0.35–0.53, p < 0.001) with WR in all phases of the sprint. Thigh attached WR provides a means to significantly increase rotational work specific to sprinting.

To succeed in full contact combat sports like mixed martial arts, tae kwon do, and boxing, athletes must deliver a greater number of damaging strikes than they receive. Producing knockdowns, rendering unconsciousness, and scoring points can be accomplished through the application of high magnitudes of striking forces. There is evidence that striking forces can be enhanced through either nonspecific or specific strength and conditioning methods or a combination thereof. To better assist practitioners working with combat sport athletes, this article reviews current empirical evidence on how combat sport athletes respond to different methods of resistance training and offers practical recommendations for implementing nonspecific and specific exercises.