This study examined the effects of dietary weight loss and exercise on the health-related quality of life (HRQL) of overweight and obese, older adults with knee osteoarthritis. A total of 316 older men and women with documented evidence of knee osteoarthritis were randomly assigned to 1 of 4 18-month interventions: dietary weight loss, exercise, dietary weight loss and exercise, or healthy lifestyle control. Measures included the SF-36 Health Survey and satisfaction with body function and appearance. Results revealed that the combined diet and exercise intervention had the most consistent, positive effect on HRQL compared with the control group; however, findings were restricted to measures of physical health or psychological outcomes that are related to the physical self.

These results support the PASE's validity for the assessment of physical activity among older adults with pain and disability.

This review suggests that physical activity and diet programs are beneficial, specifically for pain relief (9 grade A recommendations) and improved functional status (6 grade A and 7 grade C+ recommendations), for adults with OA who are obese or overweight. The Ottawa Panel was able to demonstrate that when comparing physical activity alone, diet alone, physical activity combined with diet, and control groups, the intervention including physical activity and diet produced the most beneficial results.

Summary Objective To examine the effects of dietary weight loss, with and without exercise, on selected soluble biomarkers in overweight and obese older adults with symptomatic knee OA. Design Blood samples were analyzed from 429 participants in the IDEA trial randomized to either an 18 month exericse control group (E), weight loss diet (D), or D+E. C1M, C2M, C3M and CRPM biomarkers and IL-6 were quantitated using ELISAs. Radiographic progression was defined as a decrease in joint space width of ≥ 0.7mm. Statistical modeling of group means and associations used mixed models adjusted for visit, baseline BMI, gender, and baseline values of the outcome. Results Compared to the E control group, C1M was significantly lower in the D and D+E groups at both 6 and 18 months while C3M was significantly lower in D and D+E at 6 months and in D+E at 18 months. C2M did not change in any group. Using data from all groups, change in C1M (p<0.0001), C3M (p<0.0001), as well as CRPM (p=0.0004) from baseline to 18 months was positively associated with change in weight. No marker was associated with change in WOMAC pain or radiographic progression. C3M (p=0.008) and CRPM (p=0.028) were positively associated with change in WOMAC function. Change in IL-6 was positively associated with change in C1M, C3M, and CRPM. Conclusion Overweight and obese adults with knee OA who lost weight from diet and diet plus exercise reduced serum markers of interstitial matrix turnover and inflammation but not type II collagen degradation.

Results: There was no significant difference between groups in % MVIC. In the comparison with in groups, there was no significant difference in co-activation due to the contraction level in the operative and nonoperative side of the TKA group. Co-activation during 20% MVIC (0.05) in the senior group showed a significantly lower value compared to 100% MVIC (0.22) and 80% MVIC (0.20) (p<0.05). In the young group, coactivation during 100% MVIC (0.18) was significantly higher than coactivation at all other levels (80% MVIC ¼ 0.10, 60% MVIC ¼ 0.06, 40% MVIC ¼ 0.05 and 20% MVIC ¼ 0.03) (p< 0.05).Conclusions: An understanding of the postoperative changes in hamstrings and quadriceps muscle function is important to optimize rehabilitation after TKA. The results of this study showed that the senior group and young group differed in co-activation due to the contraction intensity of the knee extensor muscles, but the difference was not observed in the TKA group. It was reported that the simultaneous contraction of the quadriceps contributed to joint stability while increasing joint pressure. TKA patients may have a disorder of the neuromuscular control mechanism which makes it difficult to perform appropriate simultaneous contraction according the contraction force. We suggest that it may be important to be careful of excessive co-activation in patients after TKA, because excessive co-activation may influence posture control and cause gait disturbance after TKA. Further investigation is necessary to understand muscle function in TKA patients.