Lower Extremity Emg for an Experienced Runner During Deep Water Running

There is lack of research investigating muscle activity patterns during deep water running (DWR). The purpose of the study was to establish a technique to describe lower extremity muscle activity patterns during DWR. A female subject (age: 23yo; mass: 58kg; ht: 1.7m), experienced with TMR and DWR, wore an Aqua-Jogger Belt while tethered to the poolside. Prior to testing and following a warm-up/familiarization period, target DWR cadences and TMR speeds were identified while the subject exercised during moderate (M) and moderate-hard (MH) intensities. Bipolar leads were used to record right side Vastus Lateralis (VL) and Biceps Femoris (BF) muscle activity using telemetry EMG. Leads were covered with a hard shell and waterproofed using Tegaderm patches and vaseline. During each condition, data were recorded (1kHz) over 30s and processed using a digital integrator and lowpass filter (fc = 66Hz) followed by a 100 point moving average routine. For each EMG record, 15 consecutive peak VL points were identified. Data between two peaks represented a repetitive cycle and ensemble curves were created for each muscle by interpolating each cycle to 101 points resulting in smooth patterns representative of overall muscle activity. The VL pattern was observed to be similar during DWR and TMR, with each pattern exhibiting a single peak pattern. The BF pattern was distinctly different during DWR vs. TMR in that the patterns were roughly 180° out of phase. Additionally, the DWR BF pattern typically had two distinct peaks while during TMR there was typically a single dominant peak. During DWR, BF peaks occurred about 10 and 42% of the cycle compared to 81% during TMR. Minimum BF activity occurred about 80% of the cycle during DWR compared to 38% during TMR. The effect of intensity on VL and BF patterns was that peak EMG increased with greater exertion but timing of peaks did not seem to be affected. The similarity of VL patterns during DWR and TMR is evidence supporting DWR as a suitable supplement to TMR. However, different BF patterns indicate that hip extensors and/or knee flexors are recruited differently during DWR and TMR.