Inclusion Criteria:  (1) Participants should be 18 years old or above; (2) no restriction of physical mobility; (3) no uncontrollable mental disorders; and (4) professional rugby-7s player.  Exclusion Criteria:  (1) less than 18 years old; (2) have restriction of physical mobility; (3) have uncontrollable mental disorders; and (4) training duration of rugby is less than one year.