To determine the presence of weakness.
Rate on 5-point scale:
0/5 - no muscle activity
1/5 - muscle twitching only
2/5 - some muscle activity, but can not overcome gravity
3/5 - overcome gravity, but not resistance
4/5 - able to overcome some resistance
5/5 - normal strength
Isokinetic dynometry machines (eg Cybex®, KinCom®) – use constant speed and variable resistance to test muscle strength.