 In micro-gravity simulations, human test subjects can experience gastrocnemius tendon strength loss of up to 58% over a 90-day period.Test subjects who were allowed to engage in resistance training displayed a smaller magnitude of tendon strength loss in the same micro-gravity environment, but modulus strength decrease was still significant.Conversely, tendons that have lost their original strength due to extended periods of inactivity can regain most of their mechanical properties through gradual re-loading of the tendon, due to the tendon's response to mechanical loading.