The relationship between single-limb squat and jump-cut kinematics.

No objective criteria exist for progressing athletes into cutting manoeuvres following ACL reconstruction (ACLR). The purpose of this study was to evaluate the relationship between a jump-cut task (JC) and the single-limb squat (SLS) in both ACLR and healthy controls. Case-control, laboratory based. Twenty-three participants with a history of ACLR (Age = 21 ± 3 years; Height = 174.5 ± 7.2 cm; Mass = 76.2 ± 9.9 kg) and 23 healthy controls participants (Age = 21 ± 3 years; Height = 173.8 ± 9.2 cm; Mass = 75.0 ± 10.5 kg) were included. Kinematics were collected bilaterally. Correlations between tasks were evaluated for kinematics. Independent sample t-tests were used to evaluate differences between groups for each dependent variable. Peak trunk rotation and medial knee displacement were strongly correlated (p < 0.001, r2 = 0.63), between tasks. ACLR group performed SLS and JC tasks with less sagittal plane motion compared to healthy controls (p < 0.05). Lack of frontal and transverse plane control during SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during JC. The SLS may be considered for use as a clinical predictor of JC during rehabilitation following ACLR.

Preventive Training Program Feedback Complexity, Movement Control, and Performance in Youth Athletes.

CONTEXT: Preventive training programs (PTPs) reduce injury risk by improving movement control. Corrective feedback is important; however, many cues at once may be too complicated for athletes. OBJECTIVE: To compare movement control and long-jump (LJ) changes in youth athletes participating in a season-long PTP, with simplified feedback, traditional feedback, or a warmup of the coaches' choosing. DESIGN: Cluster-randomized controlled trial. SETTING: Soccer fields. PATIENTS OR OTHER PARTICIPANTS: A total of 420 athletes (simplified feedback = 173, traditional feedback = 118, and control = 129; age = 11 ± 3 years). INTERVENTION(S): Teams were randomized into the simplified PTP, traditional PTP, or control group. Simplified and traditional PTPs lasted 10 to 12 minutes and used the same exercises. The simplified PTP provided only sagittal-plane feedback (eg, "get low"), and the traditional PTP provided feedback targeting all motion planes (eg, "don't let your knees cave inward"). Research assistants administered the PTP warmups 2 to 3 times/week for the season. Control team coaches chose and ran their own warmup strategies. MAIN OUTCOME MEASURE(S): Participants completed 4 sessions (preseason [PRE], postseason [POST] at approximately 8 weeks after PRE, retention 1 [R1] at 6 weeks postseason, and retention 2 [R2] at 12 weeks postseason). They performed 3 trials of a jump-landing task, which was evaluated using the Landing Error Scoring System (LESS) and 2 recorded standing LJ trials at each test session. A time series panel was used to evaluate group differences across time points for the LESS and LJ. RESULTS: Change score analyses revealed improvements in the LESS score from PRE to POST for all groups. Improvements from PRE were retained at R1 and R2 for the intervention groups (simplified and traditional). The traditional group demonstrated better LJ performance at POST (P < .001) and R1 (P = .049) than the simplified or control group. CONCLUSIONS: Simplified cues were as effective as traditional cues in improving LESS scores from PRE to POST season. Participating in PTPs, regardless of their complexity, likely provides movement benefits.

Sport Sampling Is Associated With Improved Landing Technique in Youth Athletes.

BACKGROUND: Sport sampling is recommended to promote fundamental movement skill acquisition and physical activity. In contrast, sport specialization is associated with musculoskeletal injury risk, burnout, and attrition from sport. There is limited evidence to support the influence of sport sampling on neuromuscular control, which is associated with injury risk, in youth athletes. HYPOTHESIS: Athletes who participated in only 1 sport during the previous year would demonstrate higher Landing Error Scoring System (LESS) scores than their counterparts. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 355 youth athletes (age range, 8-14 years) completed a test session with a jump-landing task, which was evaluated using the LESS. Participants were categorized as single sport (SS) or multisport (MS) based on their self-reported sport participation in the past year. Their duration of sport sampling (low, moderate, high) was determined based on their sport participation history. Participants were dichotomized into good (LESS <5) or poor (LESS ≥5) categories. Chi-square tests were performed to evaluate for the association between control category (good, poor) and participation (MS, SS), as well as sport-sampling duration (low, moderate, high). RESULTS: The MS group was 2.5 times (95% CI, 1.9-3.1) as likely to be categorized as having good control compared with the SS group (χ2(355) = 10.10, P < 0.01). Recreational participants in the "high" sport-sampling duration group were 5.8 times (95% CI, 3.1-8.5) and 5.4 times (95% CI, 4.0-6.8) as likely to be categorized as having good control compared with the moderate and low groups (χ2(216) = 11.20, P < 0.01). CONCLUSION: Sport sampling at a young age is associated with improved neuromuscular control, which may reduce injury risk in youth athletes. CLINICAL RELEVANCE: Youth athletes should be encouraged to try participating in multiple sports to enhance their neuromuscular control and promote long-term physical activity.