Dumbbell Shoulder External Rotation
Errors (upright posture)
Target muscle
moves body segment through plane perpendicular to resistance
- Force must be through the transverse plane
- Correct form
- Bottom line: with a dumbbell, perform this exercise
lying on your side
Dumbbell Triceps Kickback Errors
(elbow too low)
Effective range of motion
decreased by drop in elbow
- Triceps
Kickback (correct form) already has half the effective range
of motion as other triceps exercises
- greatest resistance occurs at full extension when weight
travels parallel to gravity
- If elbow is too low (see animation to right)
- very little effective range of motion
- exerciser typically tries to compensate and flexes arm against
gravity
- performing something that resembles a hammer curl
- even that motion compromises range of motion.
- resistance does not travel parallel to gravity at end of
motion
- possible causes
- weight could be too great
- exerciser is not bent over enough
- upper arm need to be positioned horizontal
- exerciser merely tries to bend over slightly (typically without
arm support) thinking that will do.
Shoulder Shrugs Errors (shoulder
rolls)
Rolling (horizontal movement) is
nonsensical
- Weight moves perpendicular to gravity
- In an upright posture, the upper
traps and middle
traps resist weights against gravity (downward force) as
they elevate the scapula
- Although it is true the middle
and lower trapezius
can also retract the scapula on a continuum of planes
- Bottom line: It's only necessary to raise and lower
the shoulders during shrugs. The lower and middle trapezius will
be exercised during other basic exercises
- Also see ROM
Criteria
Cable
Exercise Errors (cable perpendicular to line
of force)
- Added resistance through cable (weight stack via pulley)
is aligned perpendicular to target muscles
- does not effect difficulty of exercise
- no or little movement of weight stack during key motion of
exercise
- Correct form:
- pull of cable needs to travel:
- relatively vertical under exerciser
- approximately parallel with line of push
- Some so called exercise experts evidentally even fail to
understand this important biomechanical concept
- For example, Hammer Strength Training Vest exercise video
demonstrates numberous movements that load exercises perpendicular
to line of force of synergist muscles.
Compound Wide Grip Upper Body
Exercise Errors (too wide of grip)
Recommended
grip width for wide grip exercises
- elbow width, when elbow is same height/plane as shoulders
- subtle deviations may still be used (i.e. 2 cm narrower or
wider)
- Wider grip
- decreases range
of motion
- decreases relative involvement of assisting muscles
- Example wide grip exercises
- Also see Dip
Bar Width
Line drawings from Trainer
ClipArt. |
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