This adaptation enables one to react to various expected or unforeseen muscle loads and stresses more efficiently, with decreased caloric expenditure and risk of injury. Strengthening exercises and programmes follow the ‘specificity’ principle, sometimes referred to as Specific Adaptation to Imposed Demands [41,42,56]. For example, if one performs strength training (whether isometric or isotonic) at a specific joint angle or ROM,

one will show the most strength improvements at or around that specific angle or range [57–59]. Similarly, if one trains by performing squats (or biceps curls) exclusively, one will excel at performing squats (or curls) but will display little to no carry-over into long distance or sprint swimming, throwing or helping to prevent anterior MAPK Inhibitor Library cruciate Panobinostat manufacturer ligament injuries. Despite certain controversy in the literature as to the best approach for obtaining significant gains in absolute strength in the previously untrained individual, there seems to be a general consensus for the following: Approximately 6–8 weeks training consisting of 2–4 workouts/week, comprised of 6–10 repetitions of near maximal muscle contractions performed for 3–4 sets, with 2–4 min rest between sets [40,41,43,55,56,60–62]. Additionally there

should be a warm up and cool down period. Conversely, gains in muscular

endurance (e.g. increased mitochondrial and capillary density) allow submaximal forces to be performed repetitively, due to improved oxidative mechanisms [55]. To achieve this, the typical training recommendation is to perform lower intensity muscle contractions at higher repetitions but with lower rest intervals, when compared with absolute, maximal strength science training [56,61]. Strength training guidelines and recommendations also exist for children, namely avoiding power lifting, body building and maximal lifts until they have reached skeletal maturity [40,44,45,47]. What does this mean for the person with haemophilia (PWH) and his physiotherapists? Besides the benefits already mentioned above, increased joint and core muscle strength in PWH helps control exaggerated end-ROM joint movements & thereby may help prevent or decrease synovial impingement and associated haemarthroses or synovitis [63–65]. As noted above, to increase muscle mass and peak strength, one must train with relatively maximum resistance loads for roughly 6–10 repetitions. Consequently, with this type of training in PWH risk of injury is substantially higher as a result of the significant amounts of contractile forces and translational loads imposed across the muscles, tendons and (sometimes partially damaged) joints.