Muscle strength and exercise intensity adaptation to resistance training in older women with knee osteoarthritis and total knee arthroplasty

OBJECTIVES To analyze muscle strength and exercise intensity adaptation to resistance training in older women with knee osteoarthritis and total knee arthroplasty. METHODS Twenty-three community-dwelling women were divided into the following groups: older, with knee osteoarthritis and total knee arthroplasty in the contralateral limb (OKG; N= 7); older, without symptomatic osteoarthritis (OG; N= 8); and young and healthy (YG; N= 8). Muscle strength (1-repetition maximum strength test) and exercise intensity progression (workload increases of 5%-10% were made whenever adaptation occurred) were compared before and after 13 weeks of a twice-weekly progressive resistance-training program. RESULTS At baseline, OKG subjects displayed lower muscle strength than those in both the OG and YG. Among OKG subjects, baseline muscle strength was lower in the osteoarthritic leg than in the total arthroplasty leg. Muscle strength improved significantly during follow-up in all groups; however, greater increases were observed in the osteoarthritic leg than in the total knee arthroplasty leg in OKG subjects. Greater increases were also seen in the osteoarthritic leg of OKG than in OG and YG. The greater muscle strength increase in the osteoarthritic leg reduced the interleg difference in muscle strength in OKG subjects, and resulted in similar posttraining muscle strength between OKG and OG in two of the three exercises analyzed. Greater exercise intensity progression was also observed in OKG subjects than in both OG and YG subjects. CONCLUSIONS OKG subjects displayed greater relative muscle strength increases (osteoarthritic leg) than subjects in the YG, and greater relative exercise intensity progression than subjects in both OG and YG. These results suggest that resistance training is an effective method to counteract the lower-extremity strength deficits reported in older women with knee osteoarthritis and total knee arthroplasty.