Location of anterior knee pain affects load tolerance in isometric single leg knee extension.

OBJECTIVES: To investigate relationships between load tolerance of single leg isometric knee extension and athlete reported knee pain location and severity during the single leg decline squat. DESIGN: Cross-sectional study. METHODS: 175 college basketball athletes (99 women, 76 men) in Alberta, Canada participated at the start of the 2018-19 season. Knee pain location (dichotomized into focal/diffuse pain), and severity (numerical rating scale 0-10) were collected during the single leg decline squat. Athletes completed a standardized single leg isometric knee extension to determine load tolerance (defined by pain or reduced form). A quantile regression model was used to examine the association between load tolerance and pain location adjusting for sex, years played, body mass index and team. RESULTS: Athletes with diffuse pain had a significantly lower median load tolerance (-0.89 kg) than athletes without pain (95% confidence interval [-1.49, -0.29]; p = 0.003). Athletes with focal pain tolerated similar median loads (-0.42 kg) to those without pain (95% confidence interval [-1.17, 0.33]; p = 0.26). Higher knee pain severity was associated with a non-linear but consistent reduction in load tolerance (p < 0.001). CONCLUSIONS: Athlete-reported knee pain location during the single leg decline squat influenced load tolerance to isometric knee extension. Athletes with focal pain tolerated similar isometric loads to their pain free teammates. Clinicians should consider load selection of isometric knee extension for athletes with diffuse pain given their lower load tolerance. Future research should consider reporting pain location in addition to pain severity to differentiate clinical presentations and response to exercise.

Prevalence and Pain Distribution of Anterior Knee Pain in Collegiate Basketball Players.

CONTEXT: Causes of anterior knee pain (AKP) in jumping athletes include patellofemoral pain and patellar tendinopathy. The differential diagnosis of AKP is challenging, with variations in clinical presentations. No previous research has used pain location to describe AKP in basketball players. OBJECTIVE: To (1) describe the prevalence and pain distribution of AKP in collegiate basketball players and (2) report the prevalence of focal inferior pole pain using 2 outcome measures. DESIGN: Cross-sectional study. SETTING: University and collegiate basketball facilities in Alberta, Canada. PATIENTS OR OTHER PARTICIPANTS: A total of 242 collegiate basketball athletes (138 women, 104 men). MAIN OUTCOME MEASURE(S): The single-legged decline squat test (SLDS) was used to capture pain location via pain mapping (dichotomized as focal or diffuse) and pain severity (numeric rating scale). The Oslo Sports Trauma Research Centre Knee questionnaire (OSTRC-Knee) and adapted version for patellar tendinopathy (OSTRC-Patellar Tendinopathy Questionnaire [OSTRC-P]) were used to report the prevalence of AKP and patellar tendinopathy, respectively. Focal inferior pole pain during the SLDS was used to classify patellar tendinopathy. RESULTS: Of the 242 players, 146 (60%) reported pain with the SLDS (unilateral = 64 [26%]; bilateral = 82 [34%]). A total of 101 (43%) described knee pain using the OSTRC-Knee. Pain mapping captured the variability in pain locations. Diffuse pain was more prevalent (left, 70%; right, 72%) than focal pain (left, 30%; right, 28%). Low prevalence of patellar tendinopathy was noted using the OSTRC-P (n = 21, 8.7%) and inferior pole pain during the SLDS (n = 25, 10.3%). CONCLUSIONS: Diffuse AKP was common in Canadian basketball players; however, pain mapped to the inferior pole of the patella was not common. Few players reported tendinopathy using the OSTRC-P, suggesting that patellar tendinopathy was not a primary knee pain presentation in this jumping cohort. Pain location, rather than the presence or severity of pain alone, may better describe the clinical presentation of AKP in jumping athletes.

Validation of a commercially available inertial measurement unit for recording jump load in youth basketball players.

A high incidence of overuse knee injuries among youth basketball players may be attributed to number of jumps. Wearable technology may be an effective tool for measuring jump load compared to traditional counting methods. The purpose of this study was to validate a commercially available jump counter (VERT® Classic) in youth basketball practices and games, and to identify the characteristics (i.e., height, direction, takeoff) of jumps recorded by the VERT® Classic. 46 (19F, 27M) youth basketball players wore a VERT® Classic and were recorded on video during games and practices. The number of jumps recorded by the VERT® Classic and evaluated by video raters were compared for each jump characteristic using intraclass correlation coefficient (ICC(3,k)), mean offset, and limits of agreement. The number and percent of VERT® Classic jumps and corresponding video jumps according to timestamp were reported. VERT® Classic jumps had excellent reliability with video-counted jumps over 15 cm (ICC(3,k) = 0.958), with a mean offset of -2.4 jumps (fewer VERT® Classic) and limits of agreement -12.6 to 7.8 jumps. Pairs of corresponding jumps represented 68.0% of total video jumps and 92.0% of VERT® Classic jumps. The VERT® Classic can provide an estimate of jump load in youth basketball.