Short-term landing training attenuates landing impact and improves jump height in landing-to-jump movement

Smaller Formats of Volleyball Lead to Greater Improvements in Lower Limb Strength and Power, As Well As Reductions in Landing Forces: A Randomized Controlled Study in Girls

The purpose of this study was to compare the adaptations in muscular strength, power, and landing forces of young female volleyball players enrolled in two experimental programs: one using smaller formats of the game (SFG) and the other using larger formats of the game (LFG), with a third group serving as a control. This study employed a randomized controlled design, with an 8-week intervention period and pre- and post-intervention evaluations. Fifty-six trained/developmental participants (age: 14.7 ± 0.5 years) voluntarily participated in this study. Each experimental group received additional training twice a week. The SFG group participated in 2v2 and 3v3 formats on smaller courts (covering 2/6 of the court's available zones) with a regular net, while the LFG group played in 4v4 and 5v5 formats on larger courts (covering 4/6 of the court's available zones). Assessments were conducted using force platforms and included the following tests: (i) isometric mid-thigh pull test (IMTP), measuring peak force; (ii) squat jump test (SJ), measuring peak force; (iii) countermovement jump test (CMJ), measuring peak power and landing force; and (iv) drop jump test (DJT), measuring the reactive strength index. Significant differences emerged post-intervention across all outcomes (p < 0.05). The SFG exhibited significantly greater IMTP peak force compared to both the LFG (p = 0.012) and control groups (p = 0.035). Additionally, the SFG showed significantly greater SJ peak force than the LFG (p = 0.036) and control groups (p = 0.023). Regarding CMJ peak power, significantly higher values were observed in the SFG compared to the LFG (p = 0.042) and control groups (p = 0.046). Moreover, the SFG had significantly lower CMJ peak landing force than both the LFG (p = 0.049) and control groups (p = 0.046). Finally, RSI was significantly higher in the SFG than in the LFG (p = 0.046) and control groups (p = 0.036). This study highlights the significant benefits of incorporating 2v2 and 3v3 SFG formats to enhance muscular strength, power, and landing forces in young female volleyball players, contrasting with less effective outcomes observed with 4v4 and 5v5 LFG formats, suggesting potential neuromuscular advantages crucial for improving volleyball performance.

What do we Know about Complex-Contrast Training? A Systematic Scoping Review

BACKGROUND

The complex-contrast training (CCT) method utilizes two exercises with different loads and movement velocities in a set-by-set fashion to induce multiple neuromuscular adaptations. The speculated primary mechanism involves the post-activation potentiation or post-activation performance enhancement (PAPE) of the muscles used during the heavy load (low velocity) exercise, thereby improving the performance of lower load (high velocity) exercise. However, no previous study has attempted to systematically synthesize the available evidence on CCT (e.g., if post-activation potentiation or PAPE was measured during the training sessions during the intervention period). This study aimed to synthesize the available evidence on CCT using a systematic scoping review approach. More specifically, we identified gaps in the literature using an evidence gap map (EGM), and provided future directions for research.

METHODS

Three electronic databases (PubMed, Scopus, and Web of Science) were searched up to 20th February 2024. Data were extracted under a PICO framework: (a) Participants-related data (e.g., age, sex, type of sport); (b) Intervention-related data (e.g., duration of training); (c) Comparators (when available); and (d) Outcomes (e.g., measures of physical fitness). Interactive EGMs were created using the EPPI mapper software.

RESULTS

From the 5,695 records screened, 68 studies were eligible for inclusion, involving 1,821 participants (only 145 females from 5 studies). All CCT interventions lasted ≤ 16 weeks. More than half of the studies assessed countermovement jump, sprint, and maximal strength performances. No studies were identified which examined upper-body CCT exercises alone, and no study assessed PAPE during the CCT sessions. Overall, the available evidence was rated with a low level of confidence.

CONCLUSIONS

In conclusion, whether CCT produces a PAPE that translates into longitudinal performance gains remains unclear. Moreover, the available evidence on the effects of CCT on various outcomes provides low confidence regarding the most effective way to implement this training method, particularly among females, and beyond long-term interventions.

Effects of Therapies Involving Plyometric-Jump Training on Physical Fitness of Youth with Cerebral Palsy: A Systematic Review with Meta-Analysis

The aim of this systematic review was to assess the effects of plyometric-jump training (PJT) on the physical fitness of youth with cerebral palsy (CP) compared with controls (i.e., standard therapy). The PRISMA 2020 guidelines were followed. Eligibility was assessed using the PICOS approach. Literature searches were conducted using the PubMed, Web of Science, and SCOPUS databases. Methodological study quality was assessed using the PEDro scale. Data were meta-analyzed by applying a random-effects model to calculate Hedges' g effect sizes (ES), along with 95% confidence intervals (95% CI). The impact of heterogeneity was assessed (I2 statistic), and the certainty of evidence was determined using the GRADE approach. Eight randomized-controlled studies with low-to-moderate methodological quality were included, involving male (n = 225) and female (n = 138) youth aged 9.5 to 14.6 years. PJT interventions lasted between 8 and 12 weeks with 2-4 weekly sessions. Compared with controls, PJT improved the muscle strength (ES = 0.66 [moderate], 95% CI = 0.36-0.96, p < 0.001, I2 = 5.4%), static (ES = 0.69 [moderate], 95% CI= 0.33-1.04, p < 0.001, I2 = 0.0%) and dynamic balance (ES = 0.85 [moderate], 95% CI = 0.12-1.58, p = 0.023, I2 = 81.6%) of youth with CP. Therefore, PJT improves muscle strength and static and dynamic balance in youth with CP compared with controls. However, more high-quality randomized-controlled trials with larger sample sizes are needed to provide a more definitive recommendation regarding the use and safety of PJT to improve measures of physical fitness.

Countermovement, Hurdle, and Box Jumps: Data-Driven Exercise Selection

Apart from squat jumps, countermovement jumps (CMJ), and drop jumps, differences among other jump variations are not as well researched, making data-driven exercise selection difficult. To address this gap, this study compared selected concentric and eccentric jump parameters of maximal effort CMJ, hurdle jumps over 50 cm hurdle (HJ), and box jumps onto a 50 cm box (BJ). Twenty recreationally trained men (25.2 ± 3.5 years) performed 3 repetitions of CMJs, HJs, and BJs, each on separate days. The data were collected using force platforms and a linear position transducer. The mean of 3 trials of each jump variation was analyzed using repeated measures ANOVA and Cohen's d. Countermovement depth was significantly greater (p ≤ 0.05) and peak horizontal force significantly lower during CMJ compared to HJ and BJ. However, there were no differences in peak velocity, peak vertical and resultant force, and total impulsion time. Finally, BJ significantly decreased peak impact force by ~51% compared to CMJ and HJ. Therefore, the propulsive parameters of HJ and BJ seem to be similar to CMJ, despite CMJ having a greater countermovement depth. Furthermore, overall training load can be decreased dramatically by using BJ, which reduced peak impact force by approximately half.

Programming Plyometric-Jump Training in Soccer: A Review

The aim of this review was to describe and summarize the scientific literature on programming parameters related to jump or plyometric training in male and female soccer players of different ages and fitness levels. A literature search was conducted in the electronic databases PubMed, Web of Science and Scopus using keywords related to the main topic of this study (e.g., “ballistic” and “plyometric”). According to the PICOS framework, the population for the review was restricted to soccer players, involved in jump or plyometric training. Among 7556 identified studies, 90 were eligible for inclusion. Only 12 studies were found for females. Most studies (n = 52) were conducted with youth male players. Moreover, only 35 studies determined the effectiveness of a given jump training programming factor. Based on the limited available research, it seems that a dose of 7 weeks (1−2 sessions per week), with ~80 jumps (specific of combined types) per session, using near-maximal or maximal intensity, with adequate recovery between repetitions (<15 s), sets (≥30 s) and sessions (≥24−48 h), using progressive overload and taper strategies, using appropriate surfaces (e.g., grass), and applied in a well-rested state, when combined with other training methods, would increase the outcome of effective and safe plyometric-jump training interventions aimed at improving soccer players physical fitness. In conclusion, jump training is an effective and easy-to-administer training approach for youth, adult, male and female soccer players. However, optimal programming for plyometric-jump training in soccer is yet to be determined in future research.

The Acute Effect of Foam Rolling and Vibration Foam Rolling on Drop Jump Performance

The purpose of this study was to examine the acute effect of foam rolling and vibration foam rolling on drop jump performance. The optimal time interval between warm-up using foam rolling or vibration foam rolling and drop jump performance was identified. This study included 16 male NCAA Division I college volleyball athletes. Three interventions were performed in a randomized order: the foam rolling exercise (FRE), vibration foam rolling exercise (VFRE), and static rest (control). The drop jump was performed before interventions, as well as 2 and 5 min after interventions. The FRE exhibited higher values for drop jump height (DJH) (p = 0.001; η² = 0.382; statistical power = 0.964) and mean power generation at the hip joint (p = 0.006; η² = 0.277; statistical power = 0.857) at 2 min compared with before intervention but not at 5 min (p > 0.05). However, the VFRE showed no significant changes in DJH (p > 0.05), and found that hip_power was decreased at 5 min (p = 0.027; η² = 0.214; statistical power = 0.680). The FRE completed in 2 min before rapid single action competition (sprint, long jump, triple jump, etc.) could increase sports performance.

The Effects of Injury Prevention Programs on the Biomechanics of Landing Tasks: A Systematic Review With Meta-analysis

BACKGROUND

Anterior cruciate ligament (ACL) tear is a common injury in sports and often occurs during landing from a jump.

PURPOSE

To synthesize the evidence on the effects of injury prevention programs (IPPs) on landing biomechanics as they relate to the ligament, quadriceps, trunk, and leg dominance theories associated with ACL injury risk.

STUDY DESIGN

Meta-analysis.

METHODS

Six electronic databases were searched for studies that investigated the effect of IPPs on landing task biomechanics. Prospective studies that reported landing biomechanics at baseline and post-IPP were included. Results from trunk, hip, and knee kinematics and kinetics related to the ACL injury theories were extracted, and meta-analyses were performed when possible.

RESULTS

The criteria were met by 28 studies with a total of 466 participants. Most studies evaluated young females, bilateral landing tasks, and recreational athletes, while most variables were related to the ligament and quadriceps dominance theories. An important predictor of ACL injury, peak knee abduction moment, decreased ( P = .01) after the IPPs while other variables related to the ligament dominance theory did not change. Regarding the quadriceps dominance theory, after the IPPs, angles of hip flexion at initial contact ( P = .009), peak hip flexion ( P = .002), and peak knee flexion ( P = .007) increased, while knee flexion at initial contact did not change ( P = .18). Moreover, peak knee flexion moment decreased ( P = .005) and peak vertical ground-reaction force did not change ( P = .10).

CONCLUSION

The exercises used in IPPs might have the potential to improve landing task biomechanics related to the quadriceps dominance theory, especially increasing peak knee and hip flexion angles. Importantly, peak knee abduction moment decreased, which indicates that IPPs influence a desired movement strategy to help athletes overcome dangerous ligament dominance loads arising from lack of frontal plane control during dynamic tasks. The lack of findings for some biomechanical variables suggests that future IPPs may be enhanced by targeting participants' baseline profile deficits, highlighting the need to deliver an individualized and task-specific IPP.

Whole Body Vibration Immediately Decreases Lower Extremity Loading During the Drop Jump

Chen, Z-R, Peng, H-T, Siao, S-W, Hou, Y-T, and Wang, L-I. Whole body vibration immediately decreases lower extremity loading during the drop jump. J Strength Cond Res 30(9): 2476-2481, 2016-The purpose of this study was to evaluate the acute effect of whole body vibration (WBV) on lower extremity loading during the drop jump (DJ). Fifteen male collegiate physical education students randomly completed 3 experimental sessions on 3 separate days with 4 days interval between sessions (performing 3 trials of DJ from 30-, 40-, and 50-cm drop heights before WBV and 4 minutes after WBV). Eight cameras and 2 force platforms were used to record kinematic and kinetic data, respectively. Peak impact force and loading rate significantly decreased after WBV during DJ from 40 and 50 cm. Knee angular displacements significantly increased after WBV during DJ from 30, 40, and 50 cm. Whole body vibration may help immediately reduce lower extremity loading.

Mechanical parameters and flight phase characteristics in aquatic plyometric jumping

Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water. Kinetic force platform data from 12 young, male adults were collected for counter-movement jumps performed on land and in water at two different immersion depths. The specificity of jumps between environmental conditions was assessed using kinetic measures, temporal characteristics, and an assessment of the statistical relationship between take-off velocity and time in the air. Greater peak mechanical power was observed for jumps performed in the water, and was influenced by immersion depth. Additionally, the data suggest that, in the water, the statistical relationship between take-off velocity and time in air is quadratic. Results highlight the potential application of aquatic plyometric training as a cross-training tool for improving mechanical power and suggest that water immersion depth and fluid drag play key roles in the specificity of the take-off phase for jumping movements performed in the water.

Rehabilitation of Patellar Tendinopathy Using Hip Extensor Strengthening and Landing-Strategy Modification: Case Report With 6-Month Follow-up

Study Design Case report. Background Although eccentric exercises have been a cornerstone of the rehabilitation of athletes with patellar tendinopathy, the effectiveness of this intervention is sometimes less than ideal. Athletes with patellar tendinopathy have been shown to have different jump-landing patterns and lower hip extensor strength compared to asymptomatic athletes. To our knowledge, the effectiveness of an intervention addressing these impairments has not yet been investigated. Case Description The patient was a 21-year-old male volleyball athlete with a 9-month history of patellar tendon pain. Pain was measured with a visual analog scale. Disability was measured with the Victorian Institute of Sport Assessment-patella questionnaire. These assessments were conducted before and after an 8-week intervention, as well as at 6 months after the intervention. Hip and knee kinematics and kinetics during drop vertical jump and isometric strength were also measured before and after the 8-week intervention. The intervention consisted of hip extensor muscle strengthening and jump landing strategy modification training. The patient did not interrupt volleyball practice/competition during rehabilitation. Outcomes After the 8-week intervention and at 6 months postintervention, the athlete was completely asymptomatic during sports participation. This favorable clinical outcome was accompanied by a 50% increase in hip extensor moment, a 21% decrease in knee extensor moment, and a 26% decrease in patellar tendon force during jump landing measured at 8 weeks. Discussion This case report provides an example of how an 8-week intervention of hip muscle strengthening and jump-landing modification decreased pain and disability and improved jump-landing biomechanics in an athlete with patellar tendinopathy. Level of Evidence Therapy, level 4. J Orthop Sports Phys Ther 2015;45(11):899-909. Epub 21 Sep 2015. doi:10.2519/jospt.2015.6242.

Six weeks of core stability training improves landing kinetics among female capoeira athletes: a pilot study

Core stability training (CST) has increased in popularity among athletes and the general fitness population despite limited evidence CST programmes alone lead to improved athletic performance. In female athletes, neuromuscular training combining balance training and trunk and hip/pelvis dominant CST is suggested to reduce injury risk, and specifically peak vertical ground reaction forces (vGRF) in a drop jump landing task. However, the isolated effect of trunk dominant core stability training on vGRF during landing in female athletes had not been evaluated. Therefore, the objective of this study was to evaluate landing kinetics during a drop jump test following a CST intervention in female capoeira athletes. After giving their informed written consent, sixteen female capoeira athletes (mean ± SD age, stature, and body mass of 27.3 ± 3.7 years, 165.0 ± 4.0 cm, and 59.7 ± 6.3 kg, respectively) volunteered to participate in the training program which consisted of static and dynamic CST sessions, three times per week for six weeks. The repeated measures T-test revealed participants significantly reduced relative vGRF from pre- to post-intervention for the first (3.40 ± 0.78 vs. 2.85 ± 0.52 N·NBW-1, respectively [p<0.05, effect size = 0.60]), and second landing phase (5.09 ± 1.17 vs. 3.02 ± 0.41 N·NBW-1, respectively [p<0.001, effect size = 0.87]). The average loading rate was reduced from pre- to post-intervention during the second landing phase (30.96 ± 18.84 vs. 12.06 ± 9.83 N·NBW·s-1, respectively [p<0.01, effect size = 0.68]). The peak loading rate was reduced from pre- to post-intervention during the first (220.26 ± 111.51 vs. 120.27 ± 64.57 N·NBW·s-1 respectively [p<0.01, effect size = 0.64]), and second (99.52 ± 54.98 vs. 44.71 ± 30.34 N·NBW·s-1 respectively [p<0.01, effect size = 0.70]) landing phase. Body weight, average loading rate during the first landing phase, and jump height were not significantly different between week 0 and week 6 (p=0.528, p=0.261, and p=0.877, respectively). This study provides evidence that trunk dominant core stability training improves landing kinetics without improving jump height, and may reduce lower extremity injury risk in female athletes.