Isokinetic strength of fully operational U.S. Navy Seals with a previous history of shoulder and knee injury

Abstract

Abstract. BACKGROUND:Unintentional musculoskeletal injury has a significant impact on military personnel which is amplified in U.S. Navy Sea, Air, and Land Operators who participate in year round physical and tactical training. Full recovery from injury including restoration of strength is necessary for safe participation in training and performance of missions. Inadequate recovery may predispose the Operator to risk of future injury. OBJECTIVE: The purpose of this study was to examine isokinetic knee and shoulder strength of previously injured Operators who had returned to full duty. METHODS: Two previously injured cohorts, a knee injury group (n = 46) and a shoulder injury group (n = 55), were created from a larger group of Operators (n = 305) who had undergone strength testing. A comparison cohort was also created from each injury group (knee injury control group (n = 77) and shoulder injury control group (n = 121). All participants underwent isokinetic strength testing of their group assigned joint. This included knee flexion/extension strength testing for the knee group and shoulder internal/external rotation strength testing for the shoulder group. Side-to-side comparisons were made within each injury group and to the control group (injured extremity to strongest extremity of the control group). Individual counts within the injured Operators with strength deficits greater than 10% in their injured extremity were also performed. RESULTS: No significant side-to-side or between group differences were observed for the knee injury group. No significant side-to-side or between group differences were observed except for shoulder external rotation strength which was significantly different between groups (p = 0.003). Side-to-side strength deficits greater than 10% were observed in 20 to 25% of the injured Operators. CONCLUSION: The group comparisons demonstrate the effectiveness of the military group's rehabilitation and performance training programs, but continued vigilance and tracking of injured individuals are necessary to insure full recovery and return to duty as a small number of each injured cohort did have strength deficits bilaterally.

Isometric Knee Strength is Greater in Individuals Who Score Higher on Psychological Readiness to Return to Sport After Primary Anterior Cruciate Ligament Reconstruction

“…This protocol has been previously described in the literature, and has been shown to have good between-group and sideto-side reliability. 34,41 Average peak torque for knee flexion and knee extension were calculated and normalized to body mass in kilograms.…”

Pre-neuromusculoskeletal injury Risk factor Evaluation and Post-neuromusculoskeletal injury Assessment for Return-to-duty/activity Enhancement (PREPARE) in military service members: a prospective, observational study protocol

“…Furthermore, sub-optimal joint mobility (e.g., restricted range of motion, capsular tightness) can contribute to aberrant movement patterns [9,10] and potentially increase MSKI risks [11][12][13]. A number of potential post-MSKI physical [14][15][16][17] as well as deleterious psychosocial factors (e.g., fear of movement) may negatively impact sensorimotor function and movement quality, thereby increasing MSKI risks [18,19] and exacerbating musculoskeletal conditions [3]. While the aforementioned factors are potential risk factors for subsequent MSKI, it is also possible the risk factors preceding the initial MSKI may not have been addressed or resolved with rehabilitation and therefore may still pose a risk for future MSKI.…”