Abstract
Purpose: To evaluate time to RTT, hypothesising that the MRI appearance of the injury, classified according to the British Athletics Muscle Injury Classification (BAMIC), is associated with the type of injured tissue and its location. Method: We studied 57 male professional football players who sustained indirect muscle injuries of the biceps femoris. Inter-rater reliability between the two radiologists was assessed using the Cohen kappa (κ) coefficient. Analysis of variance (ANOVA) was used to evaluate associations between RTT and BAMIC classification, injury site, and tissue involved. Results: The injuries were categorized as myofascial, tendinous, and myotendinous. Inter-rater agreement was good (κ = 0.78). One-way ANOVA showed a significant relationship between tissue involvement and time to RTT (F = 24.16, p < 0.001). Tendinous injuries had the longest time to RTT (mean 64.3 days), followed by myotendinous injuries (mean 27.61 days) and myofascial injuries (mean 26.7 days). No statistically significant difference in time to RTT was found between the different anatomical locations (F = 1.5, p = 0.220). Conclusions: Anatomical location along the biceps femoris did not exert any influence on time to RTT. However, professional footballers who sustained myofascial injuries returned to training in less than half the time required for tendinous injuries.