Isokinetic Fatigue Ratio of Shoulder Rotators in Elite Softball Players With and Without Rotator Cuff Tendinopathy, and its Association With the Subacromial Space.

CONTEXT: Fatigue of the shoulder rotators may cause reduction of the subacromial space (SAS) and contribute to rotator cuff tendinopathy. OBJECTIVES: To compare the isokinetic peak torques and fatigue ratios of shoulder external rotators (ER) and internal rotators (IR) between elite softball athletes with and without rotator cuff tendinopathy and to investigate their associations with the SAS. DESIGN: Cross-sectional study. SETTING: University laboratory. PARTICIPANTS: Twenty-five elite softball players and 31 asymptomatic sedentary controls participated in this study. MAIN OUTCOME MEASURES: Isokinetic concentric IR and ER peak torque and fatigue ratio were measured at 60°/s and at 180°/s, respectively; and ultrasound measurement of the SAS was measured during 0° and 60° of shoulder abduction. RESULTS: Athletes with rotator cuff tendinopathy demonstrated lower peak torque in shoulder concentric ER when compared with their healthy counterparts (37.8 [5.8%] vs 43.6 [8.5%]). No significant difference was found in the fatigue ratios of ER, IR, and ER/IR when compared between elite softball athletes with and without rotator cuff tendinopathy (all P > .24). In asymptomatic athletes, greater IR peak torque (r = .583, P = .03), lower ER/IR strength ratio (r = -.605, P = .02), and greater ER/IR fatigue ratio (r = .575, P = .03) were moderately associated with more reduction of the SAS during 0° and 60° of shoulder abduction. CONCLUSIONS: Decreased strength ratio and fatigue ratio of ER/IR were related to reduction of the SAS.

Relationship between foot strike pattern, running speed, and footwear condition in recreational distance runners.

Compared to competitive runners, recreational runners appear to be more prone to injuries, which have been associated with foot strike patterns. Surprisingly, only few studies had examined the foot strike patterns outside laboratories. Therefore, this study compared the foot strike patterns in recreational runners at outdoor tracks with previously reported data. We also investigated the relationship between foot strike pattern, speed, and footwear in this cohort. Among 434 recreational runners analysed, 89.6% of them landed with rearfoot strike (RFS). Only 6.9 and 3.5% landed with midfoot and forefoot, respectively. A significant shift towards non-RFS was observed in our cohort, when compared with previously reported data. When speed increased by 1 m/s, the odds of having forefoot strike and midfoot strike relative to RFS increased by 2.3 times and 2.6 times, respectively. Runners were 9.2 times more likely to run with a forefoot strike in minimalists compared to regular running shoes, although 70% of runners in minimalists continued to use a RFS. These findings suggest that foot strike pattern may differ across running conditions and runners should consider these factors in order to mitigate potential injury.