BMI EFFECTS ON RESULTANT KNEE JOINT LOADS DURING ROWING EXERCISE AT DIFFERENT RESISTENCE LEVELS

Obesity is a global health concern, it is cause of many co–morbidities (such as osteoarthritis OA, cardiovascular disease, diabetes, hypertension, hypercholesterolaemia, etc.) that pose serious health problems, decrease quality of the life, and increase healthcare system costs. In particular, obesity is a modifiable risk factor for knee osteoarthritis (OA), because the excess body mass modifies lower extremity joint loads during locomotion [1]. So, the additional weight is responsible for potentially unhealthy joint loads in obese individuals. This condition can bring serious disability to perform activities of daily living and the risk of knee OA increase with increasing of BMI. Weight loss is critical to reducing incidence of OA and decrease the risk and/or severity of such diseases [1, 2]. The purpose of this proposal is to conduct a motion analysis experiments to study effects of BMI on knee biomechanics in rowing exercise at different resistance levels and find the correlation between changing in biomechanical parameters and BMI. Ten participant were recruited, 5 normal weight (NW, BMI = 18.5 – 24.9 kg/m2) and 5 obese (OB, BMI ?? 30 kg/m2), and the data were collected by an optoelectronic system. No differences were found due to BMI in knee adduction moment, and knee flexion angle. The results obtained for the knee flexion angle contradict conclusions in Roemer study [3]. It could be due to the absence of a very big abdominal mass in OB participants, that consented them to conduct the exercise with the same NW participants’ dynamic. Significant differences were found in maximum normalized knee extension moment and maximum normalized compressive force, between NW and OB with a resistance level equal to 3 and in both resistance levels and other two combinations (p < 0.05), respectively. Maximum knee adduction moments (KAMs) were higher in Gait than Cycling (p < 0.001), Elliptical (p < 0.001) and Rowing (p < 0.001) for NW and OB participants. Confirming the hypothesis that KAMs would depend on exercise type [4], and the rowing made no exception. The results suggest that except Gait, the other exercises may be preferred weight loss exercises aimed at limiting OA risk in OB individuals. A limitation of this study was the small sample size of participants. In order to improve evidence-based guidelines for weight loss exercises that minimize OA risk, future studies will include more participants and OW participants, and consider other biomechanical parameters and exercises.