Cardiopulmonary Responses To Submaximal Eccentric Resistance Training In Older Adults

Abstract

In non-stressful circumstances, pulmonary function in older persons is generally sufficient to maintain tissue oxygenation and metabolism with only modest increases in the work of breathing. However, with increased respiratory demands resulting from illness, physical exertion, or exercise, breathing capacity may not be adequate to supply sufficient oxygenation to the tissues. The lower cardiopulmonary requirements associated with eccentric RT may have implications for rehabilitation in populations with extreme weakness and or poor muscular endurance. PURPOSE To determine the cardiopulmonary requirements of eccentric versus concentric contractions during a bout of submaximal resistance training in older men and women. METHODS Nineteen (15 women, 4 men) volunteers, 63.4±3.6 years of age participated in the study. The subjects performed bi-lateral full squat exercises in a modified smith rack (adapted for eccentric or concentric only exercises using a pulley system). The protocol consisted of 3 sets of 10 repetitions at 65% of the concentric 1-repetition maximum strength with 2 minute rest periods between sets. Cardiopulmonary parameters including VO2, VCO2, heart rate, rate pressure product (RPP), blood pressure, estimated cardiac output, and estimated cardiac index were measured 5 min. before, during, and 5 min. post exercise using a Medical Graphics Cardio II (Medical Graphics Corporation, St. Paul. MA, BreezeSuite software version 6.0A). RESULTS Eccentric resistance training resulted in VO2, VCO2, heart rate, rate pressure product (RPP), blood pressure, estimated cardiac output, and estimated cardiac index measures that were significantly lower than during concentric resistance training. The table below shows a portion of the metabolic and cardiopulmonary data (means±SD).TableCONCLUSION Our data suggests that a bout of eccentric resistance training, at submaximal intensity, can be performed with lower cardiopulmonary requirements compared to a bout of concentric resistance training in older adults.