Performance and reference data in the jump squat at different relative loads in elite sprinters, rugby players, and soccer players

Effects of light-load vs. heavy-load jump squats as priming activities in Olympic female rugby sevens players

Priming activities have been widely used by coaches as a strategy to enhance physical performance within short periods (6-24 hours) before sport-specific training sessions and competitions. In this crossover study, we examined and compared the effects of two different priming schemes on the speed-power performance of female rugby sevens players. One hour after completing a standardized warm-up and a series of measurements including loaded and unloaded jumps and speed-related tests, twenty Olympic female rugby sevens players performed, one week apart, 6 sets of 6 reps of jump-squats (JS) at either 40% (light-load; LL) or 80% 1RM (heavy-load; HL). Countermovement jump height increased significantly 6-h after both loading conditions (ES=0.50 and 0.34, for LL and HL, respectively; P < .001), with no changes observed at the 24-h time-point. JS peak velocity improved significantly after 24-h compared to the pre-testing, but solely for the lighter loading intensity (i.e., JS at 40%1RM; ES=0.63; P=0.006). 40-m sprinting speed increased significantly at the 6-h timepoint for both LL (ES=0.20; P=0.001) and HL (ES=0.18; P=0.004), without showing significant changes in the following 24-h. COD speed improved significantly after both priming schemes at the 6- and 24-h time points, regardless of the loading condition (P ≤ 0.027 for the main effect of time). No time × loading condition interaction was detected for any variable assessed, with P-values ranging from 0.111 to 0.953. Importantly, the rate of perceived exertion was significantly higher after the priming protocol at the HL condition (P=0.02), which may lead to increased levels of fatigue and decreased performance in subsequent activities. Elite coaches from rugby sevens (and other team sports) should strongly consider these findings when programming priming training sessions in the periods preceding more intensive training sessions and official matches due to the potential disadvantages associated with the use of heavier loads (i.e., ≥ 80% 1RM).

A comparison of weighted countermovement jumps loading modes using wearable accelerometers

Background

The countermovement jump (CMJ) is an integral part of force and velocity profiling; a movement that is regularly implemented in training protocols and testing of athletic performance. Adding external loads to CMJs may have an added benefit for assessing gains in power and, in turn, monitoring progressive development. However, these added loads can displace the centre of mass of individuals, which may alter jump kinetics.

Objectives

The study aimed to evaluate kinetics across various incremental modes of loading (barbell, trapezius barbell, and dumbbell) CMJs.

Methods

Thirty-two male athletes (age: 19±2 years; height: 1.86±0.06 m, mass: 90.4±5.3 kg) completed three weighted CMJs (20, 40, 60 kg) across three bar-type modes of loading (barbell, trapezius barbell, and dumbbell). Jump metrics were measured using a wearable accelerometer. A repeated measures ANOVA was used to compare jump metrics (p<0.05).

Results

The results indicated changes in jump kinetics as added loads increased across all bar-type jump modes (p<0.001). Additionally, jump modes yielded different jump kinetics (p<0.001). Specifically, dumbbell CMJs produced the greatest force (2559 ± 462 N) and power (4861±1632 W) outputs. In contrast, the trapezius barbell consistently produced significantly (p<0.001) higher velocity (2.52±0.44 m.s-1) and acceleration (12.59±4.49 m.s-2), with the barbell never producing the highest kinetic metrics. The athletes' ranges of movement and comfort loading levels during the CMJs may be influential factors affecting vertical jump output metrics.

Conclusion

Overall, jump kinetics were altered by loads and jump types. Practically, different loading methods may target distinct jump variables allowing for individualised training programs specific for the athletes' needs.

Variations in strength-speed-power performance across the season: do true changes occur in elite rugby players?

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether "true changes" occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period (P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, "true changes" in strength-power-(but not in speed-) related qualities were consistently observed over the competitive season.

Resistance Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part III)

In the final part of this three-article collection on the training strategies of Brazilian Olympic sprint and jump coaches, we provide a detailed description of the resistance training methods and exercises most commonly employed by these speed experts. Always with the objective of maximizing the sprint and jump capabilities of their athletes, these experienced coaches primarily utilize variable, eccentric, concentric, machine-based, isometric, complex, and isoinertial resistance training methods in their daily practices. Squats (in their different forms), Olympic weightlifting, ballistics, hip thrusts, lunges, calf raises, core exercises, leg curls, stiff-leg deadlifts, and leg extension are the most commonly prescribed exercises in their training programs, during both the preparatory and competitive periods. Therefore, the current manuscript comprehensively describes and examines these methods, with the additional aim of extrapolating their application to other sports, especially those where sprint speed is a key performance factor.

Plyometric Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights

Plyometric training is extensively used by coaches to enhance neuromuscular performance in a wide variety of sports. Due to the high demands of sprint speed and power output in elite sprinters and jumpers, sprint and jump coaches are likely to have great knowledge on this topic. Undoubtedly, this expertise is even more pronounced for Olympic coaches, who work with some of the fastest and most powerful athletes in the world, and who are required to continually maintain these athletes at optimal performance levels. Describing and discussing the practices commonly adopted by these coaches in detail and extrapolating this experience to other sport coaching contexts and disciplines may be extremely relevant. The current article presents, explores, and illustrates the plyometric training practices of Brazilian Olympic sprint and jump coaches, with a special focus on training programming and exercise selection.

Strength and Conditioning Practices of Brazilian Olympic Sprint and Jump Coaches

Olympic coaches are likely to have adequate knowledge and implement effective training programs. This study aimed to describe and critically examine the strength and conditioning practices adopted by Brazilian Olympic sprint and jump coaches. Nineteen Olympic coaches (age: 50.2 ± 10.8 years; professional experience: 25.9 ± 13.1 years) completed a survey consisting of eight sections: 1) background information; 2) strength-power development; 3) speed training; 4) plyometrics; 5) flexibility training; 6) physical testing; 7) technology use; and 8) programming. It was noticed that coaches prioritized the development of explosiveness, power, and sprinting speed in their training programs, given the specific requirements of sprint and jump events. Nevertheless, unexpectedly, we observed: (1) large variations in the number of repetitions performed per set during resistance training in the off-season period, (2) a higher volume of resistance training prescribed during the competitive period (compared to other sports), and (3) infrequent use of traditional periodization models. These findings are probably related to the complex characteristics of modern competitive sports (e.g., congested competitive schedule) and the individual needs of sprinters and jumpers. Identification of training practices commonly used by leading track and field coaches may help practitioners and sport scientists create more effective research projects and training programs.

Impact of Sled Loads on Performance and Kinematics of Elite Sprinters and Rugby Players

PURPOSE

To examine the changes in resisted sprint performance and kinematics provoked by different sled loads in elite sprinters and rugby players.

METHODS

Eight elite male sprinters and 10 rugby union players performed 20-m sprints under 3 loading conditions (0%, 20%, and 60% body mass [BM]). Sprint time was measured in 0 to 5, 5 to 10, and 10 to 20 m, while stride length and hip, knee, and ankle angles were measured using an 8-sensor motion analysis system at the same distances.

RESULTS

Sprinters were significantly faster than rugby players in unresisted and resisted sprints using 20% BM (effect size, "ES" [90% confidence limit, CL] range: 0.65 [0.03 to 1.27]; 3.95 [3.10 to 4.81]), but these differences were not significant at 60% BM. Compared to rugby players, sprinters showed lower velocity decrement in resisted sprints using 20% BM (ES [90% CL] range: 0.75 [0.06 to 1.44]; 2.43 [0.83 to 4.02], but higher velocity decrement using 60% BM (ES [90% CL] range: 1.13 [0.43 to 1.82]; 1.46 [0.81 to 2.11]). No significant differences were detected in stride length between sprinters and rugby players for any sprint condition (ES [90% CL] range: 0.02 [-0.72 to 0.76]; 0.84 [0.13 to 1.54]). Rugby players showed higher hip flexion in resisted sprints (ES [90% CL] range: 0.30 [-0.54 to 1.14]; 1.17 [0.20 to 2.15]) and lower plantar flexion in both unresisted and resisted sprints (ES [90% CL] range: 0.78 [0.18 to 1.38]; 1.69 [1.00 to 2.38] than sprinters.

CONCLUSIONS

The alterations induced by resisted sprints in sprint velocity and running technique differed between sprinters and rugby players. Some caution should be taken with general sled loads prescriptions, especially when relative loads are based on distinct percentages of BM, as training responses vary among sports and individuals.

The Optimum Power Load: A Simple and Powerful Tool for Testing and Training

PURPOSE

The optimal power load is defined as the load that maximizes power output in a given exercise. This load can be determined through the use of various instruments, under different testing protocols. Specifically, the "optimum power load" (OPL) is derived from the load-velocity relationship, using only bar force and bar velocity in the power computation. The OPL is easily assessed using a simple incremental testing protocol, based on relative percentages of body mass. To date, several studies have examined the associations between the OPL and different sport-specific measures, as well as its acute and chronic effects on athletic performance. The aim of this brief review is to present and summarize the current evidence regarding the OPL, highlighting the main lines of research on this topic and discussing the potential applications of this novel approach for testing and training.

CONCLUSIONS

The validity and simplicity of OPL-based schemes provide strong support for their use as an alternative to more traditional strength-power training strategies. The OPL method can be effectively used by coaches and sport scientists in different sports and populations, with different purposes and configurations.