The musculoskeletal system is responsible for executing movements, and is comprised of the muscles and the skeleton of vertebrates. The close association between these two organ systems begins early in the development, as muscles insert into, and begin to exert mechanical forces known as muscle load on the immature skeleton. Muscle-based mechanical forces impact both the early development and the maintenance of the skeleton, and sensing these forces largely involves the non-dividing bone cells (osteocytes). Other skeletal cells such as the bone depositing osteoblasts, and the bone resorbing osteoclasts are also known to respond to mechanical stimuli.in teleosts Many studies have investigated the role of muscle load on the skeleton, but very few have investigated the role of muscle load on flat bones. The aim of this study was to understand the role played by muscle load in the development and maintenance of endochondrally ossifying flat bones called scleral ossicles in the zebrafish, Danio rerio. Following a period of increased muscle load, the morphology of the scleral ossicles was examined, along with the activity of osteoclasts and osteoblasts. Overall it was found that while the morphology of the ossicles were not significantly affected, the activity of osteoclasts and osteoblasts significantly changed. These findings help to understand the effects of muscle load on the development and maintenance of the skeleton on a fundamental level, and may have implications in mitigation strategies of metabolic bone disorders.