Related Clues:

• Writer's cramp, for example
• Flurry of activity
• Muscle woe
• Seizure
• Involuntary contraction
• Charley horse, e.g.
• Back ailment
• Convulsion
• More than a twitch
• Cramp
• Some kind of jerk?
• Common contraction?
• Twitch or tic
• Muscular misfire
• Burst of energy