ACSM GEI common mistakes
ACSM GEI · Understand the traps and how to avoid them.
Labels the lowering phase of a squat or the downward phase of a biceps curl as the concentric phase because it 'feels like the work.'
Conflates perceived effort with muscle action; candidates memorize 'up = concentric' without tracking which muscle is shortening versus lengthening.
What to do instead
Define the actions explicitly: concentric = muscle shortens against resistance; eccentric = muscle lengthens under tension; isometric = no change in length. Rehearse with squat, curl, and push-up examples until the phase labels are automatic.
Accepts a PAR-Q+ that contains a 'yes' answer and clears the participant for class without completing the follow-up pages.
Treats screening as paperwork to collect rather than a decision tool, and assumes 'moderate-intensity group exercise is safe for everyone.'
What to do instead
Any 'yes' triggers the follow-up questions; if a follow-up is also 'yes,' the participant needs advice/clearance from a healthcare provider before participation. Document the decision and the referral.
When a participant reports chest pressure and shortness of breath mid-class, tells them to 'take a break and rejoin when ready.'
Normalizes exercise discomfort and fear of overreacting; the instructor has not rehearsed the emergency action plan.
What to do instead
Stop the activity, assess the participant, activate the facility emergency action plan, call EMS for chest pain or other warning signs, retrieve the AED, and document the event.
Computes 70% intensity as 0.70 × (220 − age) and prescribes that number directly as the target heart rate.
Confuses %HRmax with %heart rate reserve and forgets to add resting heart rate back into the Karvonen equation.
What to do instead
Use %HRR = (HRmax − RHR) × intensity + RHR. Example: 40 years old, RHR 70, 70% → (180 − 70) × 0.70 + 70 = 147 bpm. Show the arithmetic on scratch paper before answering.
Uses 220 − age as the heart-rate max for a 66-year-old taking a beta blocker and sets the class target zone from that figure.
Treats the age formula as universal and ignores medication effects and the formula's individual error.
What to do instead
Beta blockers blunt heart-rate response, so use RPE or the talk test and defer to the prescriber's guidance; recognize 220 − age has substantial individual error and that Tanaka (208 − 0.7 × age) is often preferred for older adults.
Starts a 45-minute class with 35 minutes of continuous plyometrics and tacks on a 2-minute stretch at the end.
Equates 'harder' with 'more effective' and plans under time pressure without applying the FITT-VP framework.
What to do instead
Build a 5–10 minute dynamic warm-up, progress intensity gradually through the conditioning block, and finish with a 5–10 minute cool-down; apply frequency, intensity, time, type, volume, and progression deliberately.
Designs an entire class using only forward/backward movements such as marching, forward lunges, and biceps curls, with no lateral or rotational work.
Mirrors what is easiest to cue in a mirror and defaults to familiar sagittal-plane choreography.
What to do instead
Audit the plan for all three planes: sagittal (forward lunge), frontal (side step, lateral raise), and transverse (wood chop, torso twist); include balance and multi-planar movement for a complete workout.
Gives one instruction at the start of a combination, then faces the mirror or their own reflection without scanning participants.
Nervousness and choreography memorization pull attention inward; the instructor cues after the movement instead of before it.
What to do instead
Cue one to two counts ahead of the movement, combine verbal, visual, and kinesthetic cues, and deliberately scan the room left-center-right every few phrases.
Teaches a single intensity for the whole class and has no answer when a participant with knee pain asks for an alternative.
Plans for an idealized participant and does not prepare layers or modifications in advance.
What to do instead
Prepare two or three options (progression, base, regression) for each major exercise, including a low-impact alternative, and state them before the set begins so participants can self-select.
Tells a participant their shoulder pain is 'probably a rotator cuff tear' and provides stretches to fix it.
Wants to be helpful and confuses coaching experience with clinical diagnosis.
What to do instead
Stay within scope of practice: do not diagnose or prescribe treatment. Refer to a physician or physical therapist, document the conversation, and follow facility policy.