The August 2011 article "Age-Related Differences in Muscle Fatigue Vary by Contraction Type: A Meta-analysis" reported a counter-intuitive result: for some contraction types, particularly isometric and intermittent isometric contractions, older adults are more resistant to muscle fatigue than younger adults. The authors of the study--Keith Avin, PT, DPT, and Laura Frey-Law, PT, PhD--join moderator Carolynn Patten, PT, PhD, to discuss the results of this article and their clinical implications. Why are these differences in muscle fatigue important? What physiological or neurological factors might explain these results? What role does task complexity play? Does the term "fatigue" mean different things physiologically and perceptually?