The OPTIMA-Ex trial: Osteoporosis Prevention Through Impact and Muscle-loading Approaches to Exercise

The study is a three-arm, single blind randomised controlled exercise intervention trial. Eligible participants are randomized to 10-month, twice-weekly, either supervised high intensity resistance training, high intensity impact training or a “sham active” control group. Arm 1 – supervised heavy progressive resistance training. Participants allocated to the resistance training intervention group attend twice-weekly 45 minute instructor-led sessions performed on non-consecutive days. Six compound exercises (deadlift, back squat, bench press, overhead press, bent over row and calf raise) using olympic weights will be completed each session. For each exercise, 5 sets of 3-5 repetitions, corresponding to an intensity of 85 % of 1 repetition maximum will be performed under the supervision of a physiotherapist. Measurements of 1 RM will take place every 12 weeks to ensure sufficient progression of resistance training exercises. Compliance and weight lifted is monitored via training diaries which each participant completes at the end of each session. Arm 2 – supervised high-intensity impact loading exercise. Participants allocated to the impact training intervention group attend twice-weekly 40 minute instructor-led high intensity impact training sessions performed on non-consecutive days. Participants will be taught three fundamental upper limb loading exercises in the form of punches (jab, cross and lead hook) as well as complete three fundamental lower limb impact exercises (jump, hop and drop jump) under the supervision of a physiotherapist. The fundamental exercises will be performed throughout the remainder of the intervention period with progressively increasing height and complexity of jumps and force of landing with participants progressing from shod to barefoot after the familiarisation phase as well as the power and complexity of punching combinations to maintain an RPE of greater than 8 out of 10. Measures of punch kinematics will take place at 2, 4, 12, 24, 36 and 44 weeks using a GymAware device to ensure that participants continue to increase the loading and speed of their punches throughout the training intervention. Compliance is monitored via training diaries which each participant completes at the end of each session.