In   a   relaxed   state,   muscles   do   not   require   much   blood   and the   supply   of   blood   matches   the   muscle's   demands.   When the   muscles   are   involved   in   rhythmic   contractions,   such   as during   walking,   running   or   cycling,   the   blood   circulation   to   the muscles   increases   and   matches   the   increased   demands   of the    muscles    (unless    the    activity    is    very    intense).    When    a muscle    is    contracted    for    a    prolonged    duration,    the    blood supply     to     the     muscle     is     restricted     due     to     continuous compression   of   the   blood   vessels   by   the   muscle.   At   the   same time,   the   muscle's   requirement   for   oxygen   has   increased   due to   the   contraction,   so   the   blood   supply   to   the   muscles   is   not matching the muscles demands. When    this    chronic,    static    muscle    contraction    occurs,    your body   responds   by   sending   cells   to   the   area   that   will   lay   down fibrous   connective   tissue   within   the   muscle   to   help   re-enforce and    support    the    muscle.    Over    a    long    period    of    time,    the muscle   slowly   becomes   weaker,   more   ”leathery”,   and   painful knots or trigger points will develop in the muscle. The   most   common   cause   of   static   muscle   contraction   is   poor posture.    Poor    posture    can    occur    while    standing,    sitting, sleeping,   playing   sports,   working,   or   doing   hobbies.   The   most effective   approach   is   prevention,   which   can   be   addressed   by the individual or the activity. Individual interventions may include: • Postural education for sitting, standing and sleeping. • Stretching and strengthening exercises. • Nutritional advice. • Advice on technique and biomechanics of the activity.