Are return-to-play times longer in lower-limb muscle injuries involving the intramuscular tendon? A systematic review.

OBJECTIVES: To determine the influence of severity and direction (craniocaudal length vs cross-sectional area) of intramuscular tendon tears in the lower limb on return-to-play times, compared to muscle injuries without intramuscular tendon involvement. DESIGN: Systematic review with meta-analysis. METHODS: AMED, CINAHL, SPORTDiscus, ScienceDirect, PubMed (MEDLINE) and Web-of-Science were searched from inception to 31st July 2023, retrieving 666 records, of which nine were deemed eligible. A random-effects meta-analysis was performed on time to return-to-play for British Athletics Muscle Injury Classification 'b' vs 'c'. RESULTS: On the Quality in Prognosis Studies tool, one study had low risk of bias and eight had high risk. Using a best-evidence synthesis, no strong evidence emerged for a difference in time to return-to-play between injuries with or without intramuscular tendon involvement. Moderate evidence was found for an association between increased return-to-play time and the presence of "waviness" on magnetic resonance imaging and loss of tendon tension, but no association with longitudinal extent of tendon involvement. Pooled analysis revealed a medium effect-size difference between British Athletics Muscle Injury Classification 'b' and 'c' injuries, favouring classification 'b' (Hedges g = 0.67; 95% confidence interval 0.20 to 1.15; P = 0.002). CONCLUSIONS: It remains difficult to provide an accurate prognosis for muscle injuries involving the intramuscular tendon due to high risk of bias and moderate heterogeneity across studies. Moderate evidence favoured the prognosis for injuries at the musculotendinous junction (British Athletics Muscle Injury Classification 'b') over intratendinous injuries (British Athletics Muscle Injury Classification 'c').

The sensitivity of countermovement jump, creatine kinase and urine osmolality to 90-min of competitive match-play in elite English Championship football players 48-h post-match.

Purpose: Examine changes from 90-minutes of competitive match-play in countermovement jump (CMJ), creatine kinase (CK) and urine osmolality (Uosm) in elite football players over a season and their association to match external load.Methods: Eighteen footballers participated. CMJ, CK and Uosm were collected 24-h pre-match and 48-h post-match. Match-performance data was examined using Prozone®.Results: Post-match CK concentrations increased 49% (ES:0.66), while CMJ flight-time (FT), flight-time:contraction time ratio (FT:CT), take-off velocity (TV) and average power (AP) decreased 2.4-7.4% post-match (ES:0.39-0.63). CMJ height post-match reduced 4.2% (ES:0.35). CMJ FT and AP showed associations with high intensity distance covered (HID), high intensity number (HIN), explosive sprints (EXS) and medium intensity accelerations (r= -0.395 to -0.496). Changes in CMJ FT also displayed associations to total sprint distance (TSD), total sprint number (TSN) and medium intensity decelerations (r = -0.395-0.446). Increases in CMJ CT were associated with HIN (r=0.39), and CMJ AF with HIN, EXS and medium accelations/decelerations (r= -0.397 to 0.459) completed during the match.Conclusion: CMJ outputs from the push-off phase and countermovement phase were sensitive to change in neuromuscular fatigue. CK concentrations were sensitive to the match-play demands. This helps practitioners determine player readiness and has implications for individual recovery strategies.