LOAD DISTRIBUTION DURING SUSPENSION TRAINING EXERCISE

INTRODUCTION: Suspension training (ST) uses body weight in multi-directional movements as a form of exercise and due to its feasibility promotes a large variety of workouts within a low space occupancy. However, only few studies (1,2) investigated the load distribution during ST, especially during pulling exercises. Therefore, the aims of this study were to evaluate body inclination and ground reaction force and to predict equations to estimate the training load distribution during ST static back-row at different length of the straps. METHODS: Thirty volunteers (men=16, women=14; age=23.3±1.7years; body weight=63.9±13.3kg; height=167.9±9.2cm; Body Mass Index [BMI]=22.5±3.4kg·m-2) performed 14 static ST back-row (holding for 5s) at seven different lengths of ST device (148cm, 158cm, 168cm, 178cm, 188cm, 198cm, 208cm) ranging from the simplest to the most challenging, in 2 different elbow (flexed, extended) positions. A ST device (AINS ST FIPE, Italy) was anchored at 2.65m above a force platform. Subjects stood barefoot on the force plate, with their feet shoulder width apart positioned under the anchored point and visual reflective markers applied to subjects’ left lateral malleolus and at the acromion process. The force platform was used to evaluate the ground reaction force, whereas a video camera was used to record all the trials. The recorded videos were then analyzed to calculate the body inclination angle with respect to the horizontal plane. Ground reaction force and body inclination were used to predict training load equations trough multi-level regression models (P<0.05). RESULTS: Two multi-level regression models were created. In the first one, ground reaction force was used as dependent variable, whereas body inclination angle, body weight, height, BMI and elbow position were used as independent variables. Significant effects were found for all variables included in the model, with an Intraclass Correlation Coefficient (ICC) of 0.31. Analyzing the model, the follow-ing equation to estimate the ground reaction force was extrapolated: Load=-132.9134+0.3724671·Angle-1.299028·Body weight+0.9844512·Height+3.675008·BMI-2.073684·Elbow. In the second model (ICC of 0.37), the body inclination angle was replaced by the ST device’s length. By analyzing this model, the following equation to estimate the ground reaction force knowing the length of the straps was extrapolated: Load=-69.80267- 0.2199257·Length-1.281452·Body weight+0.8883487·Height+3.624841·BMI+5.188559·Elbow. CONCLUSION: The proposed models could provide different methods to quantify the training load distribution, even if the use of the straps’ length could result easier and faster than body inclination angle, helping practitioners and instructors to personalize the workout to reach specific purposes and provide load progression. References 1) Giancotti et. al., J Strength Cond Res, 2018. 2) Gulmez, J Strength Cond Res, 2017. Key-words: body weight; instability; back-row; resistance training; functional training; biomechanics