This article is from the Fitness FAQ, by Jeff Gleixner (glex@cray.com) with numerous contributions by others.
From: Tim Mansfield <timbomb@cs.uq.oz.au>
This is a summary of an interview with John Parillo entitled "Form vs
Structure" by Greg Zulak, Musclemag International, #136, September
1993.
Parillo argues in the interview that what some people take to be
genetic differences between two trainees, who do the same exercise but
gain different results, may in fact be the result of differing exercise
form. Small differences in the execution of the exercise can stress
entirely different muscles or parts of muscles.
Exercise variation muscles exercised ----------------------------------------------------------------------- Bent Row pinch shoulder blades rhomboids, trapezius shoulders down lats, teres bar to stomach rear delt, lower lat as well Chins lean back upper lats, teres lean forward, knees up lower lats Pulldowns stay vertical, pull elbows to bottom, not back, shoulders down at bottom of movement lower lats arched back, elbows behind upper lats Bent Lateral straighten arms at top rear delt leave arms bent, pinch shoulder blades rhomboids Behind Neck Press keep shoulders lowered at the top Bench Press sternum arched, shoulders down and back pecs chest flat, shoulders raised front delt Flyes as for bench press Tricep Extensions elbows wide, bar moves straight tricep belly elbows in, bar moves in an arc tricep heads Bicep curls supinated (palm down?) at top outside head pronated (palm up?) at top inside head Squats hips forward at start of raise thighs hips back and up at start lower back, glutes narrow stance, toes forward, push with balls of feet front thigh wider stance, toes out, push with heels outer thigh Calf Raises toes straight, heels turned in at the top inner head toes straight, heels turned out at the top outer head seated, feet under body soleus Stiff-Legged Deadlifts arched back, pivot from hip hamstrings rounded back, pivot from lower back lower back (dangerous) arched back, pivot from hips drive hips forward at 2/3 point, squeeze glutes glutes
 
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