The Influence Of Exercise Surface Inclination On Trunk And Lower Extremity Muscle Activity During Common Pilates Exercises

Pilates is a common series of exercises used for both clinical and general populations that incorporates a variety of body positions to vary exercise intensity. Several studies have examined muscle activity while performing Pilates exercise, however the effect of surface inclination on muscle activity is limited. PURPOSE: The purpose of this study is to compare muscle activity of the lower legs and trunk during common Pilates exercises performed at different angles of support. METHODS: Three male and eleven female college aged students (24.1±4.4yrs; 1.7±0.1m; 62.2±17.9kg) were recruited. All subjects performed 4 static (10 second hold) Pilates exercises (boat pose, bridge, plank, and single leg balance) during each of the three surface inclinations: 1) 17° incline, 2) floor, 3) 17° decline. The unilateral muscle activity of the external oblique (EO), rectus abdominus (RA), erector spinae (ES), gluteus medius (MED) and maximus (GM), tibialis anterior (TA), peroneals (PL), and the medial gastrocnemius (GAS) on the right side of the body were recorded using surface electrodes. The average root mean square of muscle activity over three trials was expressed as a percent of the individual muscles maximum voluntary contraction (MVIC) recorded at the beginning of the data collection. The %MVIC for each muscle group were compared using 1-way repeated measures ANOVAs for each pose during the three inclination conditions. RESULTS: During the boat pose, %MVIC for the RA was greater in the incline (46%) compared to the decline (19%, p = 0.002) and floor (28%, p = 0.027). During the decline plank, the %MVIC for the EO (43%) was greater in comparison to both the floor (35%, p=0.028) and the incline (29%, p = 0.005). The RA muscle activity also showed increased activity when on the decline (30%) in comparison to the incline (20%, p=0.036). The single leg balance pose showed greater activation of the TA muscle on the incline (27%) in comparison to the floor (19%, p=0.013). No differences were detected during the bridge pose. CONCLUSION: The results of this study suggest that trunk muscle activity can be altered by modifying the inclination angle. Such modifications may be useful in planning exercise progressions. Further investigation is required to examine the influence of surface inclination angle and long-term training benefits.