Response of Knee Joint Biomechanics to Landing Under Internal and External Focus of Attention in Female Volleyball Players

The aim of this study was to examine the effect of attentional focus instructions on the biomechanical variables associated with the risk of anterior cruciate ligament injury of the knee joint during a drop landing task using a time series analysis. Ten female volleyball players (age: 20.4 ± 0.8 years, height: 169.7 ± 7.1 cm, mass: 57.6 ± 3.1 kg, experience: 6.3 ± 0.8 years) performed landings from a 50 cm height under three different attentional focus conditions: (1) external focus (focus on landing as soft as possible), (2) internal focus (focus on bending your knees when you land), and (3) control (no-focus instruction). Statistical parameter mapping in the sagittal plane during the crucial first 30% of landing time showed a significant effect of attentional focus instructions. Despite the similarity in landing performance across foci instructions, adopting an external focus instruction promoted reduced vertical ground reaction force and lower sagittal flexion moment during the first 30% of execution time compared to internal focus, suggesting reduced knee loading. Therefore, adopting an external focus of attention was suggested to reduce most biomechanical risk variables in the sagittal plane associated with anterior cruciate ligament injuries, compared to internal focus and control condition. No significant differences were found in the frontal and horizontal planes between the conditions during this crucial interval.

Differences in training load, jump performance and injury occurrence in elite youth volleyball players

BACKGROUND

External and internal training load are used to monitor training effects in volleyball. Occurrence of injuries in volleyball is dependent of training loads and state of fitness but also playing positions and gender. This study aims to investigate the impact of gender and playing positions on injury occurrence among young volleyball players, considering both training loads and fitness levels.

METHODS

Conducted from September 2021 to May 2022, this study involved 37 elite young volleyball players, comprising 16 female (176.8±3.6 cm; 65.3±5.7 kg; 13.9±1.1 years old) and 21 males (189.6±7.3 cm; 77.4±9.5 kg; 14.7±1.2 years old). G-Vert accelerometer was used to quantify training load. During these sessions, RPE, state of fitness and occurrence of injuries, were collected using a daily questionnaire.

RESULTS

The primary findings indicate that males demonstrated a higher number of jumps, mean intensity, mean training load per session, and reported higher fitness levels compared to females (P<0.001). However, females were more injured than males (P<0.001). Setters were identified as the players with the highest jump frequency, albeit at lower heights and intensities than their counterparts (P<0.001). Among males, middle blockers exhibited the highest mean intensity and training load per session (P<0.01).

CONCLUSIONS

The elevated frequency of injuries and a worse reported fitness levels among females, despite lower training loads, suggests a potential deficiency in physical preparation among young women, particularly in terms of their ability to perform repeated high-intensity jumps.

Causal inference did not detect any effect of jump load on knee complaints in elite men's volleyball

The aim was to determine how jump load affects knee complaints in elite men's volleyball. We collected data from four men's premier league volleyball teams through three seasons in a prospective cohort study (65 players, 102 player-seasons). Vert inertial measurement devices captured the jump load (jump frequency and jump height) from 21 088 daily player sessions, and knee complaints were reported in 3568 weekly OSTRC-O questionnaires. Mixed complementary log-log regression models described the probability of (i) experiencing symptoms if players were currently asymptomatic, (ii) worsening symptoms if players had symptoms, and (iii) recovery from knee complaints. Based on our causal assumptions, weekly jump load was modeled as the independent variable, adjusted for age (years), weight (kg), position on volleyball team, and past jump load. No certain evidence of an association was found between weekly jump load and probability of (i) knee complaints (p from 0.10 to 0.32 for three restricted cubic splines of load), (ii) worsening symptoms if the player already had symptoms (p from 0.11 to 0.97), (iii) recovery (p from 0.36 to 0.63). The probability of knee complaints was highest for above-average weekly jump load (~1.2% for an outside hitter with mean age and height) compared with low loads (~1%) and very high loads (→ ~ 0%). The association between jump load and knee complaints risk remains unclear. Small differences in risk across observed jump load levels were observed. It would likely require substantially increased sample sizes to detect this association with certainty.

Beyond the Jump: A Scoping Review of External Training Load Metrics in Volleyball

CONTEXT

Volleyball is a complex sport involving multifaceted movements and high-velocity actions, leading to diverse external training loads (ETLs) that have profound implications for player performance and injury risk.

OBJECTIVE

To provide a comprehensive overview of the measurement of ETL in volleyball, identify gaps in current understanding, and offer valuable insights for stakeholders in the field.

DATA SOURCES

The literature search was conducted across the following electronic databases: PubMed/Medline, Scopus, Web of Science, and SPORTDiscus.

STUDY SELECTION

Studies were selected based on their relevance to the measurement of ETL in volleyball.

STUDY DESIGN

A scoping review methodology was chosen to map and summarize the broad body of literature related to ETL measurement in volleyball.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Data related to ETL measurements in volleyball were extracted and analyzed from the selected studies, focusing on metrics utilized, player positions examined, and technologies employed.

RESULTS

A total of 18 studies related to ETL in volleyball were identified and examined for this review. Despite the importance of sagittal plane movements in volleyball, the review identified a substantial research gap regarding ETL measurements beyond this plane, as well as a lack of focus on the unique demands of different player positions like the liberos. The use of technologies such as inertial measurement units was prevalent, but more comprehensive measurement methods are needed.

CONCLUSION

There is a critical need for diversified ETL metrics in volleyball, extending beyond the conventional sagittal plane measurements. The findings highlight a substantial research gap in addressing the unique demands of different player positions, notably the liberos. This study underscores the importance of incorporating multiplanar movement data, player-specific roles, and advanced measurement technologies to develop more tailored training programs and injury prevention strategies.

From data to action: a scoping review of wearable technologies and biomechanical assessments informing injury prevention strategies in sport

BACKGROUND

The purpose of this scoping review was to evaluate the current use of technologies in sports settings for training adaptation and injury prevention. The review aimed to map the existing literature, identify key concepts and themes, and highlight gaps in research, thus offering guidance for future studies.

METHODS

This study followed the guidelines of the PRISMA extension for scoping reviews and a search in four major databases was conducted.

RESULTS

A total of 21 studies were included. The findings highlighted the widespread use of various technologies, including wearable devices and force plates, to monitor athletes' performance and inform evidence-based decision-making in training and injury prevention. Variables such as Player Load, changes of direction, and acute chronic workload ratio were identified as key metrics in injury prediction.

CONCLUSIONS

This review uncovers a dynamic field of research in athlete injury prevention, emphasizing the extensive use of varied technologies. A key finding is the pivotal role of Player Load data, which offers nuanced insights for customizing training loads according to sport-specific demands, player positions, and the physical requirements of various activities. Additionally, the review sheds light on the utility of tools like force plates in assessing fatigue, aiding recovery, and steering injury rehabilitation, particularly in sports prone to knee and ankle injuries. These insights not only enhance our understanding of injury prevention but also provide a strategic direction for future research, aiming to boost athlete safety, performance, and career longevity.

Relationships between surrogate measures of mechanical and psychophysiological load, patellar tendon adaptations, and neuromuscular performance in NCAA division I men's volleyball athletes

Introduction

Patellar tendon adaptations occur in response to mechanical load. Appropriate loading is necessary to elicit positive adaptations with increased risk of injury and decreased performance likely if loading exceeds the capacity of the tendon. The aim of the current study was to examine intra-individual associations between workloads and patellar tendon properties and neuromuscular performance in collegiate volleyball athletes.

Methods

National Collegiate Athletics Association Division I men's volleyball athletes (n = 16, age: 20.33 ± 1.15 years, height: 193.50 ± 6.50 cm, body mass: 84.32 ± 7.99 kg, bodyfat%: 13.18 ± 4.72%) competing across 9 weeks of in-season competition participated. Daily measurements of external workloads (i.e., jump count) and internal workloads [i.e., session rating of perceived exertion (sRPE)] were recorded. Weekly measurements included neuromuscular performance assessments (i.e., countermovement jump, drop jump), and ultrasound images of the patellar tendon to evaluate structural adaptations. Repeated measures correlations (r-rm) assessed intra-individual associations among performance and patellar tendon metrics.

Results

Workload measures exhibited significant negative small to moderate (r-rm =-0.26-0.31) associations with neuromuscular performance, negative (r-rm = -0.21-0.30), and positive (r-rm = 0.20-0.32) small to moderate associations with patellar tendon properties.

Discussion

Monitoring change in tendon composition and performance adaptations alongside workloads may inform evidence-based frameworks toward managing and reducing the risk of the development of patellar tendinopathy in collegiate men's volleyball athletes.

Within-week differences in external training load demands in elite volleyball players

Purpose

The aim of this study was to analyze the within-week differences in external training intensity in different microcycles considering different playing positions in women elite volleyball players.

Methods

The training and match data were collected during the 2020–2021 season, which included 10 friendly matches, 41 league matches and 11 champions league matches. The players’ position, training/match duration, training/match load, local positioning system (LPS) total distance, LPS jumps, accelerations, decelerations, high metabolic load distance (HMLD), acute and chronic (AC) mean and AC ratio calculated with the rolling average (RA) method and the exponentially weighted moving average (EWMA) method, monotony and strain values were analyzed.

Results

All the variables except strain, Acc/Dec ratio and acute mean (RA) showed significant differences among distance to match days. Regarding the players’ positions, the only difference was found in the AC ratio (EWMA); in all microcycles, the middle blocker player showed workload values when compared with the left hitter, setter and libero.

Conclusion

Overall, the analysis revealed that the intensity of all performance indicators, except for strain, acc/dec and acute mean load (RA), showed significant differences among distance to match day with moderate to large effect sizes. When comparing players’ positions, the middle blocker accumulated the lowest loads. There were no significant differences among other positions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-022-00568-1.

Within-Week Variations and Relationships between Internal and External Intensities Occurring in Male Professional Volleyball Training Sessions

The purpose of the study was to test the within-week variations of the internal and external training intensity outcomes organized by days of the week. An 8-month observational period was conducted during the 2020–2021 season. The training sessions and matches of an elite volleyball team were monitored daily. The data comes from 14 players (two setters, five middle blockers, five outside hitters, and two opposites) of an elite team from the Portuguese 1st League (age: 21.7 ± 4.19 years of age; experience: 6.2 ± 3.8 years; body mass: 85.7 ± 8.69 kg; height: 192.4 ± 6.25 cm; BMI: 23.1 ± 1.40 kg/m²). The CR10 Borg scale was applied daily to measure the training intensity. The rate of perceived exertion (RPE) and the session-RPE were extracted as the internal outcomes. The external intensity was measured using an inertial measurement unit (IMU). The number of jumps, height average of jumps (JHA), minimum jump (MJ), maximal jump (MXJ), range jump (RJ), number of jumps (NJ), and training session density (D) were extracted as external intensity outcomes. The results showed that there was a difference between RPE and S-RPE (F (1.98) = 6.31, p = 0.01, η² = 0.36, and F (1.73) = 28.30, p = 0.001, η² = 0.72), as well as JHA and NJ (F (2.14) = 4.76, p = 0.02, η² = 0.30, and F (1.77) = 4.77, p = 0.02, η² = 0.30) within the microcycle. When analyzing the correlations between internal and external intensity, it was observed that there was a negative correlation between the Maximum Jump (4, 3, and 1 days before the Match day) (r² = 0.34, r² = 0.40, r² = 0.41, respectively) and the Range Jump (3 and 1 days before the Match day (r² = 0.33, r² = 0.38, respectively) with the RPE (4 days before the Match day) and Maximum Jump (5, 4, 3, and 1 days before the Match day (r² = 0.35, r² = 0.39, r² = 0.44, r² = 0.34, respectively) and Range Jump (5, 4, 3, and 1 days before the Match day) (r² = 0.34, r² = 0.35, r² = 0.40 and r² = 0.36, respectively) with S_RPE (4 days before the Match day). Such findings show that higher internal intensities are correlated with lower external intensities in sessions further away from the game day. Such results could be an important tool for coaches to reflect, plan, monitor, and execute the training unit according to the temporal distance to the competition.