Influence of Second-Generation Oral Contraceptives on Muscle Recovery after Repeated Resistance Exercise in Trained Females.

PURPOSE: Oral contraceptives (OCs) are commonly used by female athletes, but their effects on skeletal muscle are still poorly understood. We investigated if physically trained females using second-generation OCs differed from nonusers of OCs in the recovery of muscle function and muscle damage markers after repeated resistance exercise sessions. METHODS: We recruited 20 trained second-generation OC users and 20 trained nonusers to perform three strenuous resistance exercise sessions. Before, and 3, 24, and 48 h after exercise, blood samples were collected, and participants were evaluated for muscle soreness, maximal isometric and isokinetic muscle strength, vertical jump height, Wingate power performance, leg press strength, and intermittent recovery capacity (yo-yo test). All participants were provided with an energy-macronutrient-balanced diet during the experimental period. RESULTS: After resistance exercise, maximal isometric and isokinetic muscle strength, rate of force development, vertical jump height, and Wingate peak and average power were reduced, whereas markers of muscle damage were increased in both groups (P < 0.05). OC users experienced a greater reduction in isokinetic strength 3, 24, and 48 h after exercise compared with nonusers of OCs (interaction: P < 0.05). No other interactions were observed. CONCLUSIONS: We demonstrate that measures of muscle strength recovery after three strenuous resistance exercise sessions are comparable between trained females using second-generation OCs and nonusers of OCs. However, group differences were observed for isolated dynamic (isokinetic) muscle strength, suggesting a marginal benefit of not using OCs when accelerated recovery is needed.

Intra-Tester and Inter-Tester Reliability of the Lachmeter When Measuring Knee Joint Laxity.

Knee injuries are common among all age groups, and clinical knee examination is essential for the prognosis, follow-up, and rehabilitation process. The Lachmeter is a newly developed digitized modification of the Rolimeter, making it easier and faster for the test personnel to read the test result. In the present study, we aimed to evaluate the intra-tester and inter-tester reliability of the Lachmeter when testing healthy and traumatic knees. 24 healthy participants and a smaller sample of six ACL patients were examined with the Lachmeter by two intermediate testers and re-examined on a second visit within 21 days. All measurements were performed using two different grip techniques: a Lachman grip and an anterior drawer grip. Intra- and inter-tester reliability was evaluated using intra-class correlation coefficient (ICC), standard error of measurement (SEM), smallest detectable change (SDC), Student's paired t-test, and Bland-Altman plots. The results showed in healthy subjects poor to good intra-tester reliability (ICC range: -0.28-0.87, SEM range: 0.33-1.14 mm, and SDC range: 0.91-3.17 mm) and inter-tester reliability (ICC range: 0.41-0.87, SEM range: 0.27-0.67 mm, and SDC range: 0.75-1.87 mm). In ACL patients, intra-tester reliability was moderate to excellent (ICC range: 0.53-0.94, SEM range: 0.14-0.88 mm, and SDC range: 0.38-2.44 mm), with the exception of one measurement (ICC: 0.26 95% CI [-3.43; 0.89]), whereas inter-tester reliability was overall good (ICC range: 0.61-0.89, SEM range: 0.29-0.71 mm, and SDC range: 0.79-1.97 mm). Reliability measures between grip techniques indicated that the Lachman grip was more reliable than the anterior drawer grip. In conclusion, the Lachmeter showed variation between reliability measures, ranging from poor to good in healthy subjects and moderate to excellent in ACL patients. Future studies are needed to validate the Lachmeter against a gold-standard knee laxity assessment.