Muscle activity during different styles of deep water running and comparison to treadmill running at matched stride frequency

Determining if muscle activity is related to preferred stride frequency during running in the water and on land

“…PSF was defined as the SF during TMR and DWR when a subject is directed to run at a comfortable pace to complete a 30-min exercise (Liebenberg et al 2011;Masumoto et al 2013a;Mercer et al 2014).…”

“…The customized 1.5 m cables for each EMG lead and electrogoniometer were connected to a telemetry transmitting unit so that the transmitting unit was held above water level for all DWR conditions. EMG data were obtained from the following muscles on the right side using dual electrodes (Dual electrodes-272, Noraxon): the rectus femoris (RF), the long head of the biceps femoris (BF), tibialis anterior (TA), and the gastrocnemius lateralis (GL) (Masumoto et al 2009(Masumoto et al , 2013a. The sites for electrode placement were prepared by shaving the hair and abrading the skin using a skin preparation gel (Skinpure, YZ-0019, Nihon Kohden, Japan).…”

“…The electrodes were placed over the middle point of the muscle belly longitudinally along the muscle fibers (Hermens et al 2000) with a ground placed in combination with the RF lead as per manufacturer design. Additionally, waterproof dressings (Foam Pad, 75A, Nihon Kohden, Japan) were placed over all of the electrodes and ground leads (Masumoto et al 2009(Masumoto et al , 2013aMasumoto and Mercer 2008). Furthermore, subjects wore a full-body dry suit (BARE Watersports, Ultra Dry, Medium) during DWR tests (Masumoto et al 2009(Masumoto et al , 2013aMasumoto and Mercer 2008;Mercer et al 2005bMercer et al , 2014, to prevent water leakage.…”

“…This mode of exercise can be used in rehabilitation programs for runners with overuse injuries as well as a way to supplement mileage in run training programs for healthy runners. Although there has been research on physiological (e.g., Brown et al 1997;Frangolias and Rhodes 1995;Frangolias et al 1996;Masumoto et al 2009Masumoto et al , 2014Mercer and Jensen 1998;Phillips et al 2008) and biomechanical (e.g., Killgore et al 2006;Masumoto et al 2009Masumoto et al , 2013aMasumoto et al , 2014Mercer et al 2005b, 1 3 2014) parameters during DWR, there are still questions about how to best prescribe the use of this mode of exercise and which features during DWR are similar to running on land.…”

“…Although there are some data on muscle activity during DWR when using the same stride frequency (SF) as used during TMR (Masumoto et al 2013a), it is not clear if the muscle activity is optimized when running at the modespecific PSF, since there are no published data comparing what happens when SF is intentionally manipulated around the mode-specific PSF. In this context, muscle activity would be considered to be optimized at if it were either maximized or minimized compared to using SFs other than PSF.…”