Although exercise-related knee laxity changes were more pronounced in females, there was a subset of both males and females who experienced substantial knee laxity increases during exercise. Whether these individuals are more susceptible to higher-risk lower extremity biomechanics and injury risk later in a game or practice is currently under investigation.

Background The initiation and progression of knee and hip arthritis have been related to limb loading during ambulation. Although altered gait mechanics with unilateral lower limb loss often result in larger and more prolonged forces through the intact limb, how these forces differ with traumatic limb loss and duration of ambulation have not been well described.Questions/purposes The purpose of this study was to determine whether biomechanical variables of joint and limb loading (external adduction moments, vertical ground reaction force loading rates, and impulses) are larger in the intact limb of servicemembers with versus without unilateral lower limb loss and whether intact limb loading differs between shorter (B 6 months) versus longer (C 2 years) durations of ambulation with a prosthesis. 4.45-16.79; 10.18-12.81] 4.64-14.47; 8.26-9.74 82-19.51; 12.98-15.05]; ES = 0.43; p = 0.001), respectively. Intact limb mean and peak vertical ground reaction force loading rates were also larger in subjects with transfemoral limb loss with B 6 months and C 2 years of experience ambulating with a prosthesis versus control subjects .68] versus 9.03 BW/s [4.64-14.47; 8.26-9.74]; ES C 0.53; p \ 0.001;.05]; ES C 0.68; p \ 0.001, respectively). Similarly, intact limb vertical ground reaction force impulses ; ES C 0.53, p \ 0.001) were also larger among both groups of transfemoral subjects versus control subjects, respectively. Limb loading variables were not statistically different between times ambulating with a prosthesis within groups with transtibial or transfemoral limb loss. Conclusions Larger intact limb loading in individuals with traumatic transtibial loss were only noted early in the rehabilitation process, but these variables were present early and late in the rehabilitation process for those with transfemoral limb loss. Such evidence suggests an increased risk for early onset and progression of arthritis in the intact limb, especially in those with transfemoral limb loss. Clinical Relevance Interventions should focus on correcting modifiable gait mechanics associated with arthritis, particularly among individuals with transfemoral limb loss, to potentially mitigate the development and progression in this population.versus 9.03 BW/s [

The results indicate that vertical-jump performance is maintained along with progressive biomechanical changes commonly associated with decreased performance. A better understanding of lower-extremity biomechanics during explosive actions in response to IEP allows us to further develop and individualize performance training programs.

Context: Hip-joint laxity may be a relevant anterior cruciate ligament injury risk factor. With no devices currently available to measure hip laxity, it is important to determine if clinical measurements sufficiently capture passive displacement of the hip.Objective: To examine agreement between hip internalexternal-rotation range of motion measured clinically (HIER ROM ) versus internal-external-rotation laxity measured at a fixed load (HIER LAX ) and to determine their relationships with knee laxity (anterior- Conclusions: Although HIER ROM and HIER LAX differed in magnitude, they were measured with similar consistency and precision and were similarly correlated with knee laxity and GJL measures. Individuals with greater GJL also had greater hip laxity. These findings are relevant to clinicians and investigators conducting prospective risk factor studies, given the need for accessible, efficient, and low-cost alternatives for characterizing an individual's laxity profile.Key Words: anterior cruciate ligament injuries, risk factors, lower extremity Key PointsDifferences between measures of hip internal-external-rotation range of motion and laxity were large and systematic, even though the measures demonstrated comparable precision and were strongly correlated in relative magnitude. Measures of hip internal-external-rotation range of motion and laxity were strongly correlated with measures of knee laxity and general joint laxity. Clinical measurement of hip internal-external-rotation range of motion may be a reliable, efficient, and low-cost measure of passive hip-joint displacement.