Acute effects of countermovement jumping and sprinting on shot put performance

Can Blood Flow Restriction Training Benefit Post-Activation Potentiation? A Systematic Review of Controlled Trials

(1) Background: post-activation potentiation (PAP) plays an essential role in enhancing athletic performance. Various conditioning activities (CAs) have been developed to generate PAP before training or competitions. However, whether extra equipment can enhance the effectiveness of CAs is understudied. Hence, this systematic review aims to introduce and examine the effectiveness of blood flow restriction-based conditioning activities (BFR-CAs). (2) Methods: a literature search was conducted via Web of Science, PubMed, SPORTDiscus, and CNKI (a Chinese academic database). The systematic review included the literature concerning BFR-CAs and non-BFR-CAs. The methodological quality of included studies was considered to be "moderate quality" and "good quality" based on the Physiotherapy Evidence Database Scale. (3) Results: five studies were included in this study. Four studies were on lower limb strength training, and three of them suggested a greater PAP in BFR-CAs than in non-BFR counterparts. One study on upper limb strength training also supported the advantage of BFR-CAs. (4) Conclusions: BFR-CAs may be an emerging and promising strategy to generate PAP. Compared with non-BFR-CAs, BFR-CAs might be more efficient and practical for inexperienced sports people or athletes in non-power sports.

Does a linear position transducer placed on a stick and belt provide sufficient validity and reliability of countermovement jump performance outcomes?

Manufacturers recommend that linear position transducers (LPTs) should be placed on the side of a barbell (or wooden dowel) to measure countermovement jump (CMJ) height, but the validity and reliability of this placement have not been compared to other attachment sites. Since this recommended attachment site is far from the centre of mass, a belt attachment where the LPT is placed between the feet may increase the validity and reliability of CMJ data. Thirty-six physical education students participated in the study (24.6 ± 4.3 years; 177.0 ± 7.7 cm; 77.2 ± 9.0 kg). Parameters from the two LPT attachments (barbell and belt) were simultaneously validated to force plate data, where the nature of bias was analysed (systematic vs random). The within-session and between-session reliability of both attachment sites were compared to force plate data using a test-retest protocol of two sets of 5 CMJs separated by 7 days. The LPT provided highly reliable and valid measures of peak force, mean force, mean power, and jump height, where the bias was mostly systematic (r² > 0.7; ICC > 0.9). Peak velocity, mean velocity, and peak power were in very good agreement with the force plate and were highly reliable (r² > 0.5; ICC > 0.7). Therefore, both attachment sites produced similar results with a systematic bias compared to force plate data. Thus, both attachment sites seem to be valid for assessing CMJs when the measuring tool and site remain consistent across measurements. However, if LPT data are to be compared to force plate data, recalculation equations should be used.

Preconditioning Strategies Before Maximum Clean Performance in Female Weigthlifters

Kelekian, GK, Zaras, N, Stasinaki, AN, Spiliopoulou, P, Karampatsos, G, Bogdanis, G, and Terzis, G. Preconditioning strategies before maximum clean performance in female weightlifters. J Strength Cond Res XX(X): 000-000, 2020-The aim of the study was to examine the acute effect of performing clean pulls with either 85% or 120% one repetition maximum (1RM), on subsequent clean performance, in female Olympic weightlifters. Eight competitive female Olympic weightlifters (age, 22.9 ± 5.8 years; height, 1.67 ± 0.06 m; training experience, 6.1 ± 3.9 years; clean performance, 66.3 ± 3.9 kg), performed clean pulls either with 85% or with 120% 1RM, 3 minutes before their maximum effort in clean, in 2 different days, in a counterbalanced order. The rate of perceived exertion (RPE) was provided after each intervention. Body composition (dual x-ray absorptiometry), countermovement jumping (CMJ) performance, leg press isometric rate of force development (RFD), and peak force (PF) were also evaluated on different days. Clean performance was increased by 6.1 ± 3.6% (p = 0.002) after preconditioning with 85% 1RM and 4.7 ± 3.1% (p = 0.004) after 120% 1RM. Rate of perceived exertion was lower after preconditioning with 85% 1RM, compared with 120% 1RM (p = 0.015). No significant correlation was found between the changes in clean performance after 85% or 120% 1RM, with lean body mass, CMJ performance, and isometric leg press RFD, and leg press PF. These data suggest that lifting either 85% or 120% 1RM in clean pulls is an effective strategy for acute increase of clean performance in female Olympic weightlifters, whereas the use of 85% 1RM load may be performed with less exertion.

The Effects of Physical Fitness on Postactivation Potentiation in Professional Soccer Athletes

Guerra, MA Jr, Caldas, LA, Souza, HL, Tallis, J, Duncan, MJ, and Guimarães-Ferreira, L. The effects of physical fitness on postactivation potentiation in professional soccer athletes. J Strength Cond Res XX(X): 000-000, 2020-To investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response.

Acute Effect of Upper and Lower Body Postactivation Exercises on Shot Put Performance

Kontou, EI, Berberidou, FT, Pilianidis, TC, Mantzouranis, NI, and Methenitis, SK. Acute effect of upper and lower body postactivation exercises on shot put performance. J Strength Cond Res 32(4): 970-982, 2018-The purpose of this study was to investigate the effect of different types of upper and lower' extremities exercises on acute increase of shot put performance, in moderate experienced throwers. Eight (n = 8) males and 9 (n = 9) female throwers participated in this study. Their bench press and squat maximum strength were measured while their shot put performance from power position was evaluated before and after 4 interventions: (a) plyometric push-ups (Plyo), (b) 6 s isometric push-ups (Iso), (c) 3 countermovement jumps (CMJs) and (d) 10 reps. of skipping (Skip). Interventions were performed in counterbalanced order with a 48-hour interval. Significant increase (p < 0.05) of shot put performances was observed after Plyo, Iso, and CMJ (range: 2.30 ± 1.82%-5.72 ± 4.32%). In addition, Iso induced the highest increase while Skip did not induce any improvement of throwing performance. The highest increases were recorded in men's performance after CMJ (5.72 ± 4.32%) while in women's performance after Iso (3.59 ± 2.7%). Javelin and discus throwers increase higher their performance after CMJs while shot putters after Iso. Significant correlations were found between training experience, maximum/relative strength, shot put performance and increase of throwing performance (%) after the interventions (r: 0.519-0.991, p < 0.05). Percentage increase of performance between Iso and Plyo have negative correlations (r: -0.569, p < 0.05) in contrast of those between Skip and CMJ (r: 0.710, p < 0.05). These results suggest that upper or lower body postactivation interventions may acutely increase the throwing performance. However, experience and strength are significant determinant of this increase.

Acute Effect of Countermovement Jumping on Throwing Performance in Track and Field Athletes During Competition

Karampatsos, GP, Korfiatis, PG, Zaras, ND, Georgiadis, GV, and Terzis, GD. Acute effect of countermovement jumping on throwing performance in track and field athletes during competition. J Strength Cond Res 32(1): 359-364, 2017-The purpose of the study was to investigate whether performing 3 consecutive countermovement jumps (CMJs) just before an attempt enhances performance in track and field throwers during competition. Twelve shot putters, 8 hammer throwers, 9 discus throwers, and 3 javelin throwers of both sexes participated in the study. They performed 3 maximal CMJs 85 ± 12 seconds before the second, fourth, and sixth attempt during 3 different official competitions of national level. Maximal strength (1 repetition maximum [1RM]) in squat and bench press was measured 1 week after the competition. Mean throwing performance was significantly higher after the CMJs intervention (2.66 ± 4.3%, range of increase 0.02-18.98%, p = 0.0001). Similarly, maximum throwing performance was significantly higher after the CMJs (2.76 ± 3.29%, range of increase 0.09-13.93%, p = 0.0009). All but 2 athletes increased their best performance after the CMJs. The percentage increase in performance was similar between sexes (male athletes 2.56 ± 3.01%; female athletes 3.06 ± 3.76%, p = 0.677), but it was higher for the "lighter throws" (discus and javelin throw: 4.66 ± 4.11%) compared with the "heavier throws" (shot and hammer throw: 1.62 ± 2.04%, p = 0.008). The percentage increase in performance was not significantly correlated with 1RM squat or bench press, anthropometric characteristics, and personal best performance. These results suggest that performing 3 CMJs approximately 1 minute before an attempt may increase track and field throwing performance during competition.

Effects of conditioning hops on drop jump and sprint performance: a randomized crossover pilot study in elite athletes

Background

It has previously been shown that conditioning activities consisting of repetitive hops have the potential to induce better drop jump (DJ) performance in recreationally active individuals. In the present pilot study, we investigated whether repetitive conditioning hops can also increase reactive jump and sprint performance in sprint-trained elite athletes competing at an international level.

Methods

Jump and sprint performances of 5 athletes were randomly assessed under 2 conditions. The control condition (CON) comprised 8 DJs and 4 trials of 30-m sprints. The intervention condition (HOP) consisted of 10 maximal repetitive two-legged hops that were conducted 10 s prior to each single DJ and sprint trial. DJ performance was analyzed using a one-dimensional ground reaction force plate. Step length (SL), contact time (CT), and sprint time (ST) during the 30-m sprints were recorded using an opto-electronic measurement system.

Results

Following the conditioning activity, DJ height and external DJ peak power were both significantly increased by 11 % compared to the control condition. All other variables did not show any significant differences between HOP and CON.

Conclusions

In the present pilot study, we were able to demonstrate large improvements in DJ performance even in sprint-trained elite athletes following a conditioning activity consisting of maximal two-legged repetitive hops. This strengthens the hypothesis that plyometric conditioning exercises can induce performance enhancements in elite athletes that are even greater than those observed in recreationally active athletes.. In addition, it appears that the transfer of these effects to other stretch-shortening cycle activities is limited, as we did not observe any changes in sprint performance following the plyometric conditioning activity.