Children's Single-Leg Landing Movement Capability Analysis According to the Type of Sport Practiced

Unilateral Plyometric Jump Training Shows Significantly More Effective than Bilateral Training in Improving Both Time to Stabilization and Peak Landing Force in Single-Leg Lend and Hold Test: A Randomized Multi-Arm Study Conducted Among Young Male Basketball Players

Enhancing peak landing forces and ensuring faster stabilization in the lower limbs during jumping activities can significantly improve performance and decrease the risk of injury among basketball players. This study aimed to compare the effects of unilateral (uPJT) and bilateral plyometric jump training (bPJT) programs on various performance measures, including countermovement jump (CMJ), squat jump (SJ), and single-leg land and hold (SLLH) test outcomes, assessed using force plates. A randomized multi-arm study design was employed, comprising two experimental groups (n = 25; uPJT and n = 25; bPJT) and one control group (n = 25), conducted with youth male regional-level basketball players (16.3 ± 0.6 years old). Participants underwent assessment twice, both before and after an 8-week intervention training period. The uPJT program exclusively involved plyometric drills (e.g., vertical jump exercises; horizontal jump exercises) focusing on single-leg exercises, whereas the bPJT program utilized drills involving both legs simultaneously. The outcomes analyzed included CMJ peak landing force, CMJ peak power, SJ peak force, SJ maximum negative displacement, SLLH time to stabilization, and SLLH peak landing force. The control group exhibited significantly greater SLLH time to stabilization compared to both the uPJT (p < 0.001) and bPJT (p < 0.030) groups. Additionally, time to stabilization was also significantly higher in bPJT than in uPJT (p = 0.042). Comparisons between groups in regards SLLH peak landing force after intervention revealed that the value was significantly smaller in uPJT than in bPJT (p = 0.043) and control (p < 0.001). In the remaining outcomes of CMJ and SJ, both uPJT and bPJT showed significant improvement compared to the control group (p > 0.05), although there was no significant difference between them. In conclusion, our study suggests that utilizing uPJT is equally effective as bPJT in enhancing performance in bilateral jump tests. However, it significantly outperforms bPJT in improving time to stabilization and peak landing forces during single-leg land and hold test. uPJT could be advantageous not for maximizing performance but also for potentially decreasing injury risk by enhancing control and balance during single-leg actions, which are common in basketball.

Coordination and coordination variability during single-leg drop jump landing in children

Coordinative patterns require experience and learning to be acquired, producing movements that offer efficient solutions to various situations and involving certain degree of variability. This coordination variability implies functionality in movement, but it can be impacted by the type of sport practice from early years. The purpose of this work is to analyze the coordination variability and coordination patterns in a specific action such as single-leg landing in children practicing gymnastics, volleyball and non-sporting children. Thirty children (15 girls) performed 10 successful trials of single-leg landing from a height of 25 cm. A motion capture system (9 cameras) was used to capture 3D thigh and shank kinematics. To identify the significant effect of children's groups on coordination and coordination variability during single-leg landing, one-dimensional Statistical Parametric Mapping (SPM) was used. Regarding the coordination patterns, in the frontal plane, during the attenuation phase of single-leg landing, the control group exhibited a higher frequency of Anti-Phase with proximal dominancy compared to the sport groups (i.e., gymnastics, and volleyball). In addition, in the sagittal plane during the second peak phase, volleyball players exhibited a higher coordination variability than the gymnastics. The children in the control group showed a greater frequency of antiphasic movements, which indicates the influence of training at an early age, being a determining factor in the increase or not of variability.

One-dimension statistical parametric mapping in lower limb biomechanical analysis: A systematic scoping review

BACKGROUND

Biomechanics significantly impacts sports performance and injury prevention. Traditional methods like discrete point analysis simplify continuous kinetic and kinematic data, while one-dimensional Statistical Parametric Mapping (spm1d) evaluates entire movement curves. Nevertheless, spm1d's application in sports and injury research is limited. As no systematic review exists, we conducted a scoping systematic review, synthesizing the current applications of spm1d across various populations, activities, and injuries. This review concludes by identifying gaps in the literature and suggesting areas for future research.

RESEARCH QUESTION

What research exists using spm1d in sports biomechanics, focusing on the lower limbs, in what populations, and what are the current research gaps?

METHODS

We searched PubMed, Embase, Web of Science, and ProQuest databases for the following search string: "(((knee) OR (hip)) OR (ankle)) OR (foot) OR (feet) AND (statistical parametric mapping)". English peer-reviewed studies assessing lower limb kinetics or kinematics in different sports or sports-related injuries were included. Reviews, meta-analyses, conference abstracts, and grey literature were excluded.

RESULTS

Our search yielded 165 papers published since 2012. Among these, 112 examined healthy individuals (67 %), and 53 focused on injured populations (33 %). Running (n = 45), cutting (n = 25), and jumping/landing (n = 18) were the most common activities. The predominant injuries were anterior cruciate ligament rupture (n = 21), chronic ankle instability (n = 18), and hip-related pain (n = 9). The main research gaps included the unbalanced populations, underrepresentation of common sports and sport-related injuries, gender inequality, a lack of studies in non-laboratory settings, a lack of studies on varied sports gear, and a lack of reporting standardization.

SIGNIFICANCE

This review spotlights crucial gaps in spm1d research within sports biomechanics. Key issues include a lack of studies beyond laboratory settings, underrepresentation of various sports and injuries, and gender disparities in research populations. Addressing these gaps can significantly enhance the application of spm1d in sports performance, injury analysis, and rehabilitation.

Children's strategies in drop-landing

Introduction

Landing is a critical motor skill included in many activities performed in the natural environment by young children. Yet, landing is critically relevance to ensure proper stability and reduce injury. Furthermore, landing is an integral part of many fundamental motor skills which have been linked to greater physical activity, sport participation, and perceived competence in children. Our aim was to examine the drop-landing strategies of young children focusing on the lower extremity with a multi-variant approach.

Methods

Forty-four children divided into four age groups (G1:3–4.5 y, G2:4.5–6 y, G3:6–7.5 y, G4:7.5–9 y) performed 20 drop-land trials in four different conditions: predictable stationary landing, running to the left, to the right, and stay in place. Fifteen reflective markers, two force plates, and ten surface electromyography (sEMG) sensors were used to collect data. MANOVAs (Group x Condition) were conducted separately for the kinematic, kinetic, and sEMG variables.

Results

Only significant group effects were found (kinematic MANOVA p = 0.039, kinetic MANOVA p = 0.007, and sEMG MANOVA p = 0.012), suggesting that younger groups (G1, G2) differed to the older groups (G3, G4). G1 showed less knee flexion and slower ankle dorsi-flexion during the braking phase compared to G3, while G2 presented smaller ankle dorsi-flexion at the braking phase and smaller ankle range of motion than G3. Overall kinetic variables analysis showed a group difference but no group differences for any single kinetic variable alone was found. Regarding sEMG, G1 during the flight phase exhibited longer tibialis anterior and hamstrings activity than G3 and G3 &amp; G4, respectively; and an earlier start of the hamstrings' impact burst than G4. In addition, distal to proximal control was primarily used by all groups to coordinate muscle activity (in response to impact) and joint motion (after impact).

Discussion

Perhaps a developmental critical point in landing performance exists at 4–5 years of age since G1 presented the largest differences among the groups. This suggests that to improve landing strategies could start around this age. Future studies should examine if playground environments that include equipment conducive to landing and practitioners in the kindergarten schools are adequate vehicles to empower this type of intervention.

Neuromuscular Strategies in Stretch-Shortening Exercises with Increasing Drop Heights: The Role of Muscle Coactivation in Leg Stiffness and Power Propulsion

When applying drop jump exercises, knowing the magnitude of the stimulus is fundamental to stabilize the leg joints and to generate movements with the highest power. The effects of different drop heights on leg muscles coactivation, leg stiffness and power propulsion were investigated in fifteen sport science students. Drop jumps from heights of 20, 30, 40, 50, and 60 cm in a random order were performed on a force platform. During each drop jump, the ground reaction force, knee angle displacement, and synchronized surface-electromyography root-mean-square (sEMG_RMS) activity (vastus lateralis, VL; vastus medialis, VM; rectus femoris, RF; biceps femoris, BF; tibialis anterior, TA and lateral gastrocnemius, LG) were recorded. The coactivation in the pre-contact phase, between VL and BF, VM and BF as well as RF and BF, was dependent on the drop height (p < 0.01; effect size (ES) ranged from 0.45 to 0.90). Leg stiffness was dependent on the drop height (p < 0.001; ES = 0.27-0.28) and was modulated by the coactivation of VM-BF (p = 0.034) and RF-BF (p = 0.046) during the braking phase. Power propulsion was also dependent on the drop height (p < 0.001; ES = 0.34); however, it was primarily modulated by the coactivation of LG-TA during the braking phase (p = 0.002). The coactivation of thigh muscles explains leg stiffness adjustments at different drop heights. On the contrary, the coactivation of shank muscles is mostly responsible for the power propulsion.