Daily cumulative load and body mass index alter knee cartilage response to running in women

• Published in: Gait & posture 2021-07, Vol.88, p.192-197
• Main Authors: Brenneman Wilson, Elora C., Gatti, Anthony A., Keir, Peter J., Maly, Monica R.
• Format: Article
• Language: English
• Subjects: Articular; Biomechanical phenomena; Cartilage; Exercise; Magnetic resonance imaging
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2021.05.030

•Low joint loading with high daily steps explained less tibial volume change after running.•Low BMI with high daily steps explained less tibial volume change after running.•Our findings suggest a role of cumulative load in tibial cartilage conditioning. It is unknown whether a greater accumulation of knee load over a typical day is related to how cartilage responds to an acute bout of loading. This information may clarify the role of habitual activity on cartilage function. Is there a relationship between change in tibial and femoral cartilage thickness, volume, and T2 relaxation time following running with daily cumulative knee load in women? Secondarily, is there a relationship between cartilage change following running and the statistical interaction of body mass index (BMI) and daily steps? Participants (n = 15) completed gait analyses and wore an accelerometer over a week. Daily cumulative knee load was the statistical interaction between tibial compressive joint reaction force (JRF) impulse with the average number of daily steps measured using accelerometry. Magnetic resonance imaging scans were acquired before and immediately after 15-min of treadmill running. Changes in tibial and femoral cartilage thickness, volume, and T2 relaxation time were calculated. Multiple linear regressions tested the associations of cartilage change outcomes with: baseline (thickness, volume, T2), JRF impulse, steps, and the interaction JRF impulse*steps. Secondarily, BMI was substituted for JRF impulse. Tibial volume change was explained by baseline volume, JRF impulse, steps, and JRF impulse*steps (R2 = 0.50, p = 0.013). Additionally, tibial volume change was explained by baseline volume, BMI, steps, and BMI*steps (R2 = 0.43, p = 0.002). Those who were more physically active with lower JRF impulse (or lower BMI) showed less change in tibial cartilage after a running exposure. This may suggest cartilage conditioning.