Gait Characteristics, Symptoms, and Function in Persons With Hip Osteoarthritis: A Longitudinal Study With 6 to 7 Years of Follow-up.

STUDY DESIGN: Longitudinal laboratory study. OBJECTIVES: (1) To compare gait characteristics between individuals with early-stage hip osteoarthritis who underwent total hip replacement (THR) and those who did not undergo THR, and (2) to evaluate whether gait characteristics, function, and symptoms declined among individuals who did not undergo THR during a 6- to 7-year follow-up. BACKGROUND: The natural history of symptoms, function, and gait changes secondary to hip osteoarthritis, including potential differences at an early stage of disease, is unknown. METHODS: Forty-three individuals (mean age, 58.9 years) with radiographic and symptomatic hip osteoarthritis participated. Outcome measures included 3-D gait analysis; self-reported pain, stiffness, and function; hip range of motion; and the six-minute walk test. Baseline comparisons between individuals who later underwent THR and those who did not undergo THR were made using independent t tests or Mann-Whitney U tests. Comparisons of baseline measures and 6- to 7-year follow-up for the nonoperated individuals were conducted with paired-samples t tests or Wilcoxon signed-rank tests (P<.05). RESULTS: Twelve (27.9%) of the 43 individuals initially evaluated had not undergone THR at the 6- to 7-year follow-up. At baseline, these individuals had larger sagittal plane hip and knee joint excursions, larger joint space width, lower body mass index, and superior self-reported function compared with the individuals who later underwent THR. At the 6- to 7-year follow-up, the individuals who did not undergo THR exhibited no decline in gait characteristics, minimum joint space, or overall function. Furthermore, their self-reported pain had significantly decreased (P = .024). CONCLUSION: Individuals who did not undergo THR during a 6- to 7-year follow-up period did not exhibit a decline in gait, function, or symptoms compared to those who underwent THR. These findings are suggestive of a phenotype of hip osteoarthritis with a very slow disease progression, particularly in regard to pain. LEVEL OF EVIDENCE: Prognosis, level 1b.

Effects of stretching on performances involving stretch-shortening cycles.

BACKGROUND: Alongside its role in athletic conditioning, stretching has commonly been integrated in warm-up routines prior to athletic performance. Numerous studies have reported detrimental acute effects on strength following stretching. Consequently, athletes have been recommended to discontinue stretching as part of warm-ups. In contrast, studies indicate that chronic stretching performed as a separate bout from training or competition may enhance performance. However, the influence of stretching on complex performances has received relatively little attention. OBJECTIVE: The purpose of this study was to review both the acute and chronic effects of stretching on performances involving the stretch-shortening cycle (SSC). METHODS: A systematic search for literature was undertaken (January 2006-December 2012) in which only randomized controlled trials (RCTs) or studies with repeated measures designs were included. The Physiotherapy Evidence Database (PEDro) rating scale was used for quality assessment of the evidence. RESULTS: The review included 43 studies, from which conflicting evidence emerged. Approximately half of the studies assessing the acute effect of static stretching reported a detrimental effect on performance, while the remainder found no effect. In contrast, dynamic stretching showed no negative effects and improved performance in half of the trials. The effect size associated with static and dynamic stretching interventions was commonly low to moderate, indicating that the effect on performance might be limited in practice. Factors were identified that might have contributed to the conflicting results reported across studies, such as type of SSC performance and carrying out dynamic activity between the stretching bout and performance. Few studies since 2006 have addressed the chronic effect of stretching on functional and sports performance. Although negative effects were not reported, robust evidence of the overall beneficial effects within current bibliographic databases remains elusive. Plausible mechanisms for the observed effects from stretching are discussed, as well as possible factors that may have contributed to contradictory findings between studies. LIMITATIONS: Considerable heterogeneity in study design and methods makes comparison between studies challenging. No regression analysis of the contribution of different predictors to variation between trials had previously been performed. Hence, predictors had to be selected on the basis of a qualitative analysis of the predictors that seemed most influential, as well as being identified in previous narrative reviews. CONCLUSION: Different types of stretching have differential acute effects on SSC performances. The recommended volume of static stretching required to increase flexibility might induce a negative acute effect on performances involving rapid SSCs, but the effect sizes of these decrements are commonly low, indicating that the acute effect on performance might be limited in practice. No negative acute effects of dynamic stretching were reported. For athletes that require great range of motion (ROM) and speed in their sport, long-term stretching successfully enhances flexibility without negatively affecting performance. Acute dynamic stretching may also be effective in inducing smaller gains in ROM prior to performance without any negative effects being observed.