Dose Response Effect of Drop Jumps on Bone Characteristics

The study aims to assess if a 16-week drop jump intervention from different heights shows different bone adaptations. Participants will complete four visits over a period of 16 weeks. An initial consultation will be conducted to ensure participants meet the inclusion criteria following participant recruitment. Estimated load being applied to the bone, will be assessed using non-invasive biomechanical procedures (Inertial Measurement Units, motion analysis, force plates) during drop jumps. Participants will be assigned a drop jump height of 0 cm, 30 cm or 60 cm based on a significant difference in external load at these heights or assigned to a control group where no jumps will be performed. Groups will be matched for body mass to ensure that jump height produces the load. The participants will be asked to perform 40 jumps (20 each side), 4 times per week ensuring jumping bouts are separated by 24 hours. Bone characteristics will be assessed via whole body dual-energy X-ray absorptiometry (DXA) scans and bilateral peripheral Quantitative Computed Tomography (pQCT) scans. Lab based jumping will take place on week 0, week 6, week 12, and week 16 to understand the loading applied during the different jump height groups. pQCT scans will take place on week 0, week 12, week 16 and DXA scans will take place week 0 and week 16. The reasoning of week 12 for pQCT being it may show a significant timepoint for bone formation during the remodelling cycle. During visits participants will complete a health screen, the Bone specific Physical Activity Questionnaire (BPAQ), a food frequency questionnaire and Pittsburgh sleep quality questionnaire alongside consent as tools to monitor any changes to participant lifestyle across the study. Differences in bone characteristics, lab measures and jump heights will be analysed between and within participants. The present study aims to use varied drop jump heights to identify an osteogenic dose response effect. Drop jumps have been previousl