RESULTS We found that none of the 19 instruments have sufficiently comprehensive reporting of measurement or feasibility performance as would be required by regulatory authorities .
INTRODUCTION In an accompanying study we reported on the content of several activity rating scales that have been used for muscle disease .
To further aid in achieving consensus we conducted a systematic review to assess the quality of the 19 activity rating scales  design ed specifically for muscle disease .
A randomized, controlled trial of creatine monohydrate in patients with mitochondrial cytopathies.
Fatigue in patients with mitochondrial cytopathies is associated with decreased basal and postactivity muscle phosphocreatine ( PCr ) . Creatine monohydrate supplementation has been shown to increase muscle PCr and high-intensity power output in healthy subjects . We studied the effects of creatine monohydrate administration ( 5 g PO b.i.d . x 14 days -- > 2 g PO b.i.d . x 7 days ) in 7 mitochondrial cytopathy patients using a r and omized , crossover design . Measurements included : activities of daily living ( visual analog scale ) ; ischemic isometric h and grip strength ( 1 min ) ; basal and postischemic exercise lactate ; evoked and voluntary contraction strength of the dorsiflexors ; nonischemic , isometric , dorsiflexion torque ( NIDFT , 2 min ) ; and aerobic cycle ergometry with pre- and post-lactate measurements .  Creatine treatment result ed in significantly ( P < 0.05 ) increased h and grip strength , NIDFT , and postexercise lactate , with no changes in the other measured variables . We concluded that creatine monohydrate increased the strength of high-intensity anaerobic and aerobic type activities in patients with mitochondrial cytopathies but had no apparent effects upon lower intensity aerobic activities
RESULTS We found that none of the 19 instruments have sufficiently comprehensive reporting of measurement or feasibility performance as would be required by regulatory authorities .
INTRODUCTION In an accompanying study we reported on the content of several activity rating scales that have been used for muscle disease .
To further aid in achieving consensus we conducted a systematic review to assess the quality of the 19 activity rating scales  design ed specifically for muscle disease .