Single leg aerobic capacity and strength in individuals with surgically repaired anterior cruciate ligaments.

OBJECTIVES: Compare single-leg aerobic capacity and strength differences between the surgically repaired ACL leg (injured) and the uninjured leg. DESIGN: Cross-sectional study. SETTING: Laboratory. PARTICIPANTS: Eight participants (5 female, 3 male, age = 23 ± 3.5 y, mass = 72.3 ± 17.3 kg, height = 169.7 ± 9.4 cm) that returned to play from ACL surgery between six and 18 months. MAIN OUTCOME MEASURES: Participants performed an aerobically-based, single-leg cycling protocol to determine maximum oxygen consumption, ventilatory threshold, heart rate, rating of perceived exertion, and maximal watts cycled. Participants also performed isokinetic knee flexion and extension on a dynamometer to assess peak torque, total work, work fatigue, and power. RESULTS: There were no statistical differences in single-leg aerobic capacity or strength outcomes between the injured and uninjured legs. CONCLUSIONS: Individuals who have had an ACL surgically repaired six to 18 months after return to play do not appear to have aerobic capacity or strength deficits between the injured leg and uninjured leg.

The Effects of Cognitive Loading on Motor Behavior in Injured Individuals: A Systematic Review.

BACKGROUND: Research suggests that individuals with musculoskeletal injury may have difficulty negotiating physical tasks when they are combined with cognitive loads. OBJECTIVE: Our objective was to conduct a systematic review to understand the effects of increased cognitive demand on movement patterns among individuals with musculoskeletal injuries. METHODS: A comprehensive search of PubMed, MEDLINE, the Cumulative Index for Nursing and Allied Health Literature (CINAHL), and SPORTDiscus was conducted to find research reports that included a population that had previously experienced an ankle, knee, or low back injury, included an uninjured control group, and assessed a dual-task paradigm. RESULTS: Forty-five full-text research reports were assessed, of which 28 studies (six ankle injury, nine knee injury, and 13 low back pain studies) were included in the review. Included studies were assessed for methodological quality and the study design extracted for analysis including the participants, cognitive and physical tasks performed, as well as outcome measures (e.g., three-dimensional kinematics, center of pressure, etc.). All studies included were cross-sectional or case-control with methodological quality scores of 17.8 ± 2.2 out of a possible 22. Twenty-five of the 28 studies found changes in motor performance with dual-task conditions compared with single tasks. Furthermore, 54% of studies reported a significant group by task interaction effect, reporting at least one alteration in injured groups' motor performance under dual-task conditions when compared with an uninjured group. CONCLUSION: The results of this systematic review indicate that motor performance is further impaired by placing a cognitive load on individuals in populations with musculoskeletal injury. More demanding tasks such as gait appear to be more affected in injured individuals than simple balance tasks. Future investigators may want to consider the difficulty of the tasks included as well as the impact of dual-task paradigms on rehabilitation programs.

The Effects of Local Vibration on Balance, Power, and Self-Reported Pain After Exercise.

CONTEXT: Muscle fatigue and acute muscle soreness occur after exercise. Application of a local vibration intervention may reduce the consequences of fatigue and soreness. OBJECTIVE: To examine the effects of a local vibration intervention after a bout of exercise on balance, power, and self-reported pain. DESIGN: Single-blind crossover study. SETTING: Laboratory. PARTICIPANTS: 19 healthy, moderately active subjects. INTERVENTIONS: After a 30-min bout of full-body exercise, subjects received either an active or a sham vibration intervention. The active vibration intervention was performed bilaterally over the muscle bellies of the triceps surae, quadriceps, hamstrings, and gluteals. At least 1 wk later, subjects repeated the bout, receiving the other vibration intervention. MAIN OUTCOME MEASURES: Static balance, dynamic balance, power, and self-reported pain were measured at baseline, after the vibration intervention, and 24 h postexercise. RESULTS: After the bout of exercise, subjects had reduced static and dynamic balance and increased self-reported pain regardless of vibration intervention. There were no differences between outcome measures between the active and sham vibration conditions. CONCLUSIONS: The local vibration intervention did not affect balance, power, or self-reported pain.