http://www.jospt.org/ryanlmizner Wed, 30 Apr 2008 09:05:25 EST 0 http://www.jospt.org/issues/articleID.1408/article_detail.asp STUDY DESIGN: Pre- and post-instruction testing in a laboratory setting. OBJECTIVES: To examine the predictive relationship between lower extremity muscle strength and the immediate post-instruction changes in landing patterns of female athletes. We hypothesized that greater strength would be associated with larger post-instruction improvements in landing patterns. BACKGROUND: Female athletes in high-demand sports may be predisposed to anterior cruciate ligament injury because of poor landing patterns. Instruction has been shown to improve landing patterns. Lower extremity muscular strength may determine the potential for instruction to alter landing patterns. METHODS AND MEASURES: Thirty-seven female collegiate athletes in high-demand sports participated. Strength was assessed in the following muscle groups: trunk extensors and flexors, hip abductors and extensors, knee flexors and extensors, and ankle plantar flexors. Strength testing was followed by kinetic and kinematic analysis of a drop vertical jump task. Athletes then received verbal instruction on how to improve their landing technique and were retested. Landing variables of interest were force absorption time, peak vertical ground reaction force (vGRF), peak knee flexion and abduction angle, and peak external knee abduction moment. Pre- and post-instruction landing variables data were compared. Linear regression models were created with strength values as independent variables and landing variables as dependent variables. RESULTS: After instruction, athletes significantly increased their force absorption time and peak knee flexion angle while decreasing their peak vGRF, peak knee abduction angle, and peak external knee abduction moment (p0.05). CONCLUSIONS: A brief instructional session promotes short-term improvements in the landing patterns of collegiate female athletes, but muscular strength was a poor predictor of the improvements.J Orthop Sports Phys Ther., Epub 10 April 2008. doi:10.2519/jospt.2008.2726KEY WORDS: ACL, biomechanics, hip, knee, motion analysis http://www.jospt.org/issues/articleID.1408/article_detail.asp http://www.jospt.org/issues/articleID.1373/article_detail.asp SYNOPSIS: The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE: Therapy, level 5.J Orthop Sports Phys Ther. 2008;38(5):246-256, published online 14 December 2007. doi:10.2519/jospt.2008.2715KEY WORDS: electrical stimulation, quadriceps strength, rehabilitation, total knee arthroplasty, TKA http://www.jospt.org/issues/articleID.1373/article_detail.asp http://www.jospt.org/issues/articleID.244/article_detail.asp Study Design: A case series.Objectives: The purpose of this case series was to assess the effect of high-intensity neuromuscular electrical stimulation (NMES) on quadriceps strength and voluntary activation following total knee arthroplasty (TKA).Background: Following TKA, patients exhibit long-term weakness of the quadriceps and diminished functional capacity compared to age-matched healthy controls. The pain and swelling that results from surgery may contribute to quadriceps weakness. The use of high-intensity NMES has previously been shown to be effective in quickly restoring quadriceps strength in patients with weakness after surgery.Methods and Measures: All patients were treated for 6 weeks, 2 to 3 visits per week, in outpatient rehabilitation. Five patients (NMES group) participated in a voluntary exercise program for both knees and NMES for the weaker knee. Three patients (exercise group) participated in a voluntary exercise program for both knees without NMES. For each treatment session, 10 isometric electrically elicited muscle contractions were administered at maximally tolerated doses to the initially weaker leg of the NMES group. Quadriceps strength and muscle activation were repeatedly assessed up to 6 months after surgery using burst superimposition techniques.Results: At 6 months, the weak NMES-treated legs of 4 of 5 patients in the NMES group had surpassed the strength of the contralateral leg. In contrast, none of the weak legs in the exercise group were stronger than the contralateral leg at 6 months. Changes in quadriceps muscle activation mirrored the changes exhibited in strength.Conclusion: When NMES was added to a voluntary exercise program, deficits in quadriceps muscle strength and activation resolved quickly after TKA. J Orthop Sports Phys Ther. 2004;34(1):21-29.Key Words: geriatric, inhibition, rehabilitation, total knee replacement http://www.jospt.org/issues/articleID.244/article_detail.asp http://www.jospt.org/issues/articleID.697/article_detail.asp Study Design: Prospective study with repeated measures. Objectives: The overall goal of this investigation was to describe the time course of recovery of impairments and function after total knee arthroplasty (TKA), as well as to provide direction for rehabilitation efforts. We hypothesized that quadriceps strength would be more strongly correlated with functional performance than knee flexion range of motion (ROM) or pain at all time periods studied before and after TKA. Background: TKA is a very common surgery, but very little is known regarding the influence of impairments on functional limitations in this population. Methods and Measures: Forty subjects, who underwent unilateral TKA followed by rehabilitation, including 6 weeks of outpatient physical therapy, were studied. Testing occurred at 5 time periods: preoperatively, and at 1, 2, 3, and 6 months after surgery. Test measures included quadriceps strength, knee ROM, timed up-and-go test, timed stair-climbing test, bodily pain, and general health and knee function questionnaires. Results: Subjects experienced significant worsening of knee ROM, quadriceps strength, and performance on functional tests 1 month after surgery. Quadriceps strength went through the greatest decline of all the physical measures assessed and never matched the strength of the uninvolved limb. All measures underwent significant improvements following the 1-month test. Quadriceps strength was the most highly correlated measure associated with functional performance at all testing sessions. Conclusions: Functional measures underwent an expected decline early after TKA, but recovery was more rapid than anticipated and long-term outcomes were better than previously reported in the literature. The high correlation between quadriceps strength and functional performance suggests that improved postoperative quadriceps strengthening could be important to enhance the potential benefits of TKA. J Orthop Sports Phys Ther. 2005;35(7):424-436. Key Words: disability, muscle, outcome, replacement http://www.jospt.org/issues/articleID.697/article_detail.asp