Preliminary evidence that low ankle-brachial index is associated with reduced bilateral hip extensor strength and functional mobility in peripheral arterial disease.

OBJECTIVE: Peripheral arterial disease (PAD) has been associated with skeletal muscle pathology, including atrophy of the affected muscles. In addition, oxidative metabolism is impaired, muscle function is reduced, and gait and mobility are restricted. We hypothesized that greater severity of symptomatic PAD would be associated with lower levels of muscle mass, strength, and endurance, and that these musculoskeletal abnormalities in turn would impair functional performance and walking ability in patients with PAD. METHODS: We assessed 22 persons with intermittent claudication from PAD in this cross-sectional pilot study. Outcome assessments included initial claudication distance and absolute claudication distance via treadmill protocols and outcomes from the 6-minute walk (6MW). Secondary outcomes included one repetition maximum strength/endurance testing of hip extensors, hip abductors, quadriceps, hamstrings, plantar flexors, pectoral, and upper back muscle groups, as well as performance-based tests of function. Univariate and stepwise multiple regression models were constructed to evaluate relationships and are presented. RESULTS: Twenty-two participants (63.6% male; mean [standard deviation] age, 73.6 [8.2] years; range, 55-85 years) were studied. Mean (standard deviation) resting ankle-brachial index (ABI) was 0.54 ([0.13]; range, 0.28-0.82), and participants ranged from having mild claudication to rest pain. Lower resting ABI was significantly associated with reduced bilateral hip extensor strength (r = 0.54; P = .007) and reduced whole body strength (r = 0.32; P = .05). In addition, lower ABI was associated with a shorter distance to first stop during the 6MW (r = 0.38; P = .05) and poorer single leg balance (r = 0.44; P = .03). Reduced bilateral hip extensor strength was also significantly associated with functional outcomes, including reduced 6MW distance to first stop (r = 0.74; P = .001), reduced 6MW distance (r = 0.75; P < .001), and reduced total short physical performance battery score (worse function; r = 0.75; P = .003). CONCLUSIONS: Our results suggest the existence of a causal pathway from a reduction in ABI to muscle atrophy and weakness, to whole body disability represented by claudication outcomes and performance-based tests of functional mobility in an older cohort with symptomatic PAD. Longitudinal outcomes from this study and future trials are required to investigate the effects of an anabolic intervention targeting the muscles involved in mobility and activities of daily living and whether an increase in muscle strength will improve symptoms of claudication and lead to improvements in other functional outcomes in patients with PAD.

The effect of ankle taping on detection of inversion-eversion movements in participants with recurrent ankle sprain.

BACKGROUND: Taping is often used to counter the proprioceptive deficit after joint injury such as ankle sprain. However, the effect of taping on proprioceptive acuity at the ankle is unclear, with conflicting findings. HYPOTHESIS: Application of tape improves detection of inversion and eversion movements at the ankle. STUDY DESIGN: Controlled laboratory study. METHODS: The 70% threshold for movement detection was measured in 16 participants with recurrent ankle sprain under 2 conditions: with the ankle taped or untaped. The threshold for movement detection was examined at 3 velocities (0.1 deg/s, 0.5 deg/s, and 2.5 deg/s) and in 2 directions (inversion and eversion). RESULTS: Application of tape significantly decreased the ability to detect movements at the ankle (P < .023). For example, at 0.5 deg/s, the 70% detection threshold was 3.40 degrees +/- 1.05 degrees in inversion and 3.49 degrees +/- 1.15 degrees in eversion at the untaped ankle, and 4.02 degrees +/- 0.86 degrees in inversion and 4.04 degrees +/- 0.89 degrees in eversion at the taped ankle. CONCLUSION: Taping the ankle decreased the ability to detect movement in the inversion-eversion plane in participants with recurrent ankle sprain. CLINICAL RELEVANCE: The findings suggest that the efficacy of taping is unlikely to be explained by an enhanced ability to detect inversion or eversion movements. However, because it has been found effective in reducing the incidence of ankle sprain, clinicians should continue taping to reduce the likelihood of resprain.