Water Vs. Land-based Squat Exercise In Postmenopausal Women: Effects On Neuromuscular Activity And Metabolic Equivalents

Abstract

Overweight and obesity are osteoarthritis (OA) risk factors. The prevalence of OA in women is higher than that of men. The squat exercise is a simple and effective strength training mode for lower extremities. The buoyancy and warm temperature of the water can reduce joint discomfort during the squat exercise. However, it is unclear the responses of neuromuscular activity (MA) and metabolic equivalents (METs) when squat exercise at different speeds was performed. PURPOSE: This study was to compare the responses of MA, rating of perceived exertion (RPE), and METs following squat exercise at slow (20bpm), medium (60bpm), and the fast as possible speed between in water and on-land in postmenopausal women. We recruited 23 postmenopausal women over the age of 50 with a BMI ≥ 24 or body fat ≥ 30%. Participants performed 15 repetitions squat exercise at medium speed, slow speed and fast speed in water and on land by random order. We measured the maximum voluntary contractions of quadriceps and hamstring muscle and standing posture oxygen consumption before exercise testing and collected RPE, METs, and MA in the exercise period. Paired-samples t tests were performed to test all parameters in water and on land. RESULTS: MA of quadriceps in water were significantly lower than that on land at three-speed squat exercise (slow: 11.95±3.93 vs 31.21±10.70, medium 17.02 ±5.31 vs.42.79±16.46, the fastest: 30.48±7.74 vs. 72.12±25.86 rms %, p<0.05). MA of hamstring was no difference between in water and on land following medium and fast-speed squat exercise. The METs in water were lower than that of on land at slow and medium speed squat exercise (slow: 1.73±0.37 vs.2.40±0.40, medium: 1.91±0.35 vs. 2.34 ±0.42, the fastest: 2.21±0.79 vs. 2.50±0.63, p<0.05). The RPE responses of squat exercise at all speeds in water were lower than that of on land (slow: 2.04±0.64 vs. 3.00±1.16, medium: 1.91±0.60 vs. 2.61 ±1.08, the fastest: 2.21±0.85 vs. 3.39±1.34, p<0.05). CONCLUSION: The responses of MA of hamstring and METs following the fastest-speed squat exercise were similar to those of on land, whereas it had a lower RPE.