Stretch induced Hypertrophy and Muscle Contraction Speed

http://www.ncbi.nlm.nih.gov/pubmed/7961225

Birds with Chronic Stretch induced muscle hypertrophy exhibited greater force and strength but perhaps alarmingly had slower maximal velocity muscle contractions.

Im optimistic that big muscles doesnt give slow reflexes however since this hypertrophy was purely stretch induced. And we have the anecdote that sprinters are extremely muscular.