Background: Physiological, metabolic, and biomechanical responses to submaximal and maximal exercise on the type D rowing ergometer (erg) have been established. The same comparisons have not been made with the dynamic (DYN) rowing erg, which was designed to simulate rowing on the water for proper training of competitive rowers. Design changes of the DYN erg include a moveable footrest and reduced handle return tension; however, the effect of these changes on rowing kinematics of trained rowers is unknown. Purpose: To compare physiological and kinematic responses to submaximal and maximal exercise on 2 rowing ergometers (DYN and type D) in trained collegiate rowers. Methods: National Collegiate Athletic Association Division I women rowers (n = 11, mean ± SD, age: 20.1 ± 1.3 years; 2,000-meter erg time: 474.76 ± 26.6 seconds) with a minimum of 3 years rowing experience volunteered to participate in the randomized, crossover design. Session 1 consisted of familiarization with rowing on the DYN and anthropometric measures. Sessions 2 and 3 were separated by 48 hours and completed in randomized order (DYN, type D). Rowers performed an incremental rowing test with the starting intensity determined from each athlete's most recent 2,000-meter type D erg time. Each stage of 7 lasted 4 minutes and wattage was increased 10-20 watts for each stage, with submaximal wattages the same for both tests. The last stage was maximal effort and the rower was instructed to cover as much distance as possible. Expired gases were collected to assess oxygen consumption (VO2) and ventilation (Ve). Heart rate (HR) was measured via portable wireless HR monitor. An eight-camera motion acquisition system tracked 30 markers placed on body landmarks in order to generate a biomechanical model of thoracic displacement. Paired t-tests were utilized to compare submaximal and peak physiological variables (HR, VO2, Ve) and rating of perceived exertion (RPE) between the DYN and type D erg tests (p = 0.05). At the maximal effort stage, paired t -tests were used to compare stroke rating (SR), stroke length, thoracic displacement angle, meters covered, and average watts (p = 0.05). Results: Height was 172.9 ± 8.1 cm and mass 69.2 ± 13.4 kg. There was no difference in the responses of HR, RPE, VO2, Ve, watts, or meters covered between the 2 ergs during submaximal and maximal stages. On the DYN, rowers had higher maximal stage SR (32.5/min vs. 40.5/min, p = 0.02), yet there was no difference between the thoracic displacements (DYN 25.2 ± 13.2°, type D 26.5 ± 4.7°, p = 0.74). Stroke length was significantly decreased on the DYN (0.8 ± 0.1 m) compared to the type D (1.4 ± 0.1 m) at the maximal stage (p < 0.001). Conclusions: No Ve, HR, VO2, or RPE differences were observed during the maximal stage. During the maximal stage effort the stroke rate was higher on the DYN while the stroke length was higher on type D. Practical Applications: Previous literature has suggested increased stroke rates may decrease the stress on lower back soft tissue. Furthermore, studies have suggested longer stroke lengths are a possible risk factor for injury to the soft tissue. The kinematic results of trained rowers from both erg types indicate that the DYN may reduce injury risk as compared to the type D.
© Copyright 2021 The Journal of Strength and Conditioning Research. National Strength & Conditioning Association. Alle Rechte vorbehalten.