We investigated muscle activity during deep water running (DWR) and treadmill running on dry land (TMR) at similar physiological responses. 9 subjects (30.7±10.4 years) participated in this study. The baseline conditions consisted of TMR at 3 ratings of perceived exertion (RPE) level (RPE 11, 13, and 15) with heart rate (HR) recorded during each condition. The target HR for each level of DWR condition was determined by the HR recorded during the TMR. Muscle activity from the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA) were measured. As originally planned, HR was not different between modes (P>0.05) and was different between exercise intensities (P<0.001). Only TA muscle activity was influenced by the interaction of mode and intensity (P<0.05). Muscle activity from the GA during DWR was significantly lower than that of TMR (a 34-48% decrease; P<0.05), although muscle activity from the remaining tested muscles were not influenced by modes of exercise (P>0.05). These observations suggest that matching HR can be recommended to produce similar magnitude of lower extremity muscle activity during DWR to that of TMR, with the exception of the GA.

Background: Triathletes typically wear a wetsuit during the swim portion of an event, but it is not clear if muscle activity is influenced by wearing a wetsuit. Purpose: To investigate if shoulder muscle activity was influenced by wearing a full-sleeve wetsuit vs. no wetsuit during dryland swimming. Methods: Participants (n=10 males; 179.1±13.2 cm; 91.2±7.25 kg; 45.6±10.5 years) completed two dry land swimming conditions on a swim ergometer: No Wetsuit (NW) and with Wetsuit (W). Electromyography (EMG) of four upper extremity muscles was recorded (Noraxon telemetry EMG, 500 Hz) during each condition: Trapezius (TRAP), Triceps (TRI), Anterior Deltoid (AD) and Posterior Deltoid (PD). Each condition lasted 90 seconds with data collected during the last 60 seconds. Resistance setting was self-selected and remained constant for both conditions. Stroke rate was controlled at 60 strokes per minute by having participants match a metronome. Average (AVG) and Root Mean Square (RMS) EMG were calculated over 45 seconds and each were compared between conditions using a paired t-test (α=0.05) for each muscle. Results: PD and AD AVG and RMS EMG were each greater (on average 40.0% and 66.8% greater, respectively) during W vs. NW (p<0.05) while neither TRAP nor TRI AVG or RMS EMG were different between conditions (p>0.05). Conclusion: The greater PD and AD muscle activity while wearing a wetsuit might affect swimming performance and /or stroke technique on long distance event.

No abstract