Objective To compare landing mechanics and neuromuscular recruitment strategies between women with semitendinosus-gracilis anterior cruciate ligament reconstruction (SG-ACLr) and non-injured women during double and single-legged drop jumps. Design Cross-sectional biomechanical study Setting Single university-based biomechanics laboratory Participants Fourteen women 1–5 years post SG-ACLr and 16 non-injured women participated in this study. Methods After anthropometric measurements, warm-up, and familiarization procedures, participants performed five trials of a double and single-legged drop jumps. Main Outcome Measurements Dynamic knee valgus was measured as the distance between knee joints during the landing phase of the double-leg drop jumps. Medial knee displacement was the outcome considered during the landing phase of the single-leg drop jumps. For both drop jumps tasks neuromuscular recruitment was evaluated through rectified normalized electromyography (EMG) activity of the quadriceps and hamstrings (amplitude and latency), and quadriceps/hamstrings EMG co-contraction ratio. Results Although the SG- ACLr group demonstrated a tendency towards a greater dynamic knee valgus during both drop jumps, these differences did not reach statistical significance. EMG data revealed different neuromuscular strategies for each group depending on the specific jump. Conclusions These findings suggest that women with SG-ACLr have a tendency towards greater dynamic knee valgus which could predispose to additional knee injuries. Rehabilitation specialists need to be aware of existing kinematic and neuromuscular deficiencies years after SG-ACLr. Taking this into consideration will aid in prescribing appropriate interventions designed to prevent re-injury.
Dynamic knee joint stability may be affected by the onset of metabolic fatigue during sports participation that could increase the risk for knee injury. The purpose of this investigation was to determine the effects of metabolic fatigue on knee muscle activation, peak knee joint angles, and peak knee internal moments in young women during 2 jumping tasks. Fifteen women (mean age: 24.6 ± 2.6 years) participated in one nonfatigued session and one fatigued session. During both sessions, peak knee landing flexion and valgus joint angles, peak knee extension and varus/valgus internal moments, electromyographic (EMG) muscle activity of the quadriceps and hamstrings, and quadriceps/hamstring EMG cocontraction ratio were measured. The tasks consisted of a single-legged drop jump from a 40-cm box and a 20-cm, up-down, repeated hop task. The fatigued session included a Wingate anaerobic protocol followed by performance of the 2 tasks. Although participants exhibited greater knee injury–predisposing factors during the fatigued session, such as lesser knee flexion joint angles, greater knee valgus joint angles, and greater varus/valgus internal joint moments for both tasks, only knee flexion during the up-down task was statistically significant (p = 0.028). Metabolic fatigue may perhaps predispose young women to knee injuries by impairing dynamic knee joint stability. Training strength-endurance components and the ability to maintain control of body movements in either rested or fatigued situations might help reduce injuries in young women athletes.
PurposeThe aim of this study was to establish the concurrent validity and reliability of four different two-dimensional (2D) video-based techniques for quantifying frontal plane knee kinematics during a 40 cm double-legged drop jump.Participants and methodsA convenience sample of 16 healthy participants (nine males and seven females; age: [mean ± standard deviation] 25.5±2 years; body mass index: 24.33±2.98 kg/m2) participated in this investigation. A total of five trials during a 40 cm drop jump maneuver with a countermovement jump were used as the functional task. Four knee valgus measures, such as two different frontal plane projection angle measures, knee-to-ankle separation ratio (KASR), and knee separation distance (KSD), were measured using 2D and three-dimensional (3D) systems. To generalize to the greater population of possible evaluators, the testers performing the biomechanical analyses were three novice physical therapists. Intra- and intertester intraclass correlation coefficients (ICCs) were estimated for 2D analysis variables. ICCs were estimated for all measures between systems to determine concurrent validity of the 2D system.ResultsAll four 2D measures showed good to excellent reliability (ICC: 0.89–0.99). KASR and KSD showed excellent correlation (ICC: 0.96; 95% CI: 0.82–0.98 and ICC: 0.94; 95% CI: 0.90–0.96, respectively) with the 3D system, while both methods of frontal plane projection angle showed poor to moderate correlation (ICC: 0–0.57) with the 3D system.Conclusion2D KASR and KSD measures are cost effective, reliable, and highly correlated with the same measures using 3D techniques for the evaluation of knee valgus.
ObjectivesPuerto Rico (PR), is the fifth highest jurisdiction of the United States of America (US) with respect to HIV prevalence and the leading in cervical cancer incidence. This cross-sectional study describes the prevalence and correlates of cervical HPV infection among a clinic-based sample of 302 women living with HIV/AIDS in PR.MethodsData collection included questionnaires, blood and cervical samples. Multivariable logistic regression models were used to estimate the magnitude of association (adjusted Prevalence odds ratio [aPOR]) between HPV cervical infection and other covariates.ResultsMean age of participants was 40.3 years (± 10.3 SD). The prevalence of HPV infection was 50.3%; 41.1% for low-risk types and 29.5% for high-risk types. Having ≥ 10 lifetime sexual partners (aPOR = 2.10, 95% CI:1.02–4.29), an abnormal Pap (aPOR = 3.58, 95% CI:1.93–6.62), active genital warts (aPOR = 3.45, 95% CI:1.60–7.42), and CD4 counts ≤ 200 (aPOR = 4.24, 95% CI: 1.67–10.78) were positively associated with any cervical HPV infection. Similar results were observed for HR HPV infection.ConclusionsA high burden of HPV co-infection exists among women living with HIV/AIDS in this population. Given the high incidence of HIV in PR and the higher risk of cervical cancer among women living with HIV/AIDS, HPV vaccination should be promoted in this population.
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