Life Participation In Strength Training May Preserve Function And Reduce Pain Burden In Knee Osteoarthritis

PURPOSE: Strength training (ST) can decrease knee osteoarthritis (OA) disability and pain. The purpose was to compare knee OA functional outcomes and pain in later life based on volume of ST participation over a lifetime. METHODS: Six-year data from the Osteoarthritis Initiative were analyzed. Participants (N = 354; at risk for OA or symptomatic for OA) were grouped based on regular ST in lifetime epochs (years): 12-18, 19-34, 35-49, >50, where ST0 = no ST during any time, and ST4 = ST in all epochs. Outcomes were compared among groups over six-years: days with activity-limiting knee pain (last 30 days); Western Ontario McMaster Osteoarthritis Index (WOMAC) function and pain scores; onset of mobility disability (walk speed <1 m/s); 5 repetition-chair rise time, 20-m walk speed; Physical Activity Score for the Elderly (PASE); OA onset at other joints; pain medication use. RESULTS: ST0 reported more pain-limited days than other groups at baseline (4.6 vs 2.6-3.5d; p = .002). WOMAC function and pain subscores in the left knee were 18-51% and 25-44% higher, respectively, in ST0 over time than other groups (p < .001). WOMAC function and pain subscores in the right knee were 19-42% (p < 0.001) and 23-30% (p = 0.002) in ST0 over time than other groups. Fewer participants in ST3 and ST4 developed mobility disability (0.4-0.6% vs 2.8-3.8%; p = <0.001). ST3 and ST4 demonstrated faster 5-repetition chair rise time and 20-m walk speed than ST1 and ST0 over six years (all p < .05). ST4 generated highest PASE scores and ST0 lowest PASE scores over time (p = .013). Six-year hand OA onset was lower in ST2 and ST3 than other groups (4.6-5.2% vs 7.0-9.2%; p = .007). Pain medication use was lowest in ST4 and highest in ST0 at baseline (6.0% vs 12.6%; p = .002). CONCLUSIONS: ST engagement during a lifetime may help preserve mobility, physical activity levels, and function while reducing the need for pain medication later in life for individuals who are at risk for OA or who have progressive OA. NATL INST OF HLTH NIAMS