During heavy lifts, form tends to slip at the end of each set. “Even though your muscles haven’t failed yet, your nervous system and coordination have, putting you at risk of injury,” says Dillon Peterson, Tier X coach at Preston Hollow in Dallas.
There are a few reasons this could happen, he notes. First, you may have skipped your warm-up, so you were never fully prepared for the set. Second, you may have chosen a rep range that was too high, so your muscles tired out. Third, you may have lost focus, worsening your form.
To avoid all that, you’d ideally warm up with 3 sets of 1 to 3 reps of your planned lift, starting with light weights and adding a few pounds throughout. For your main sets, choose a rep count 2 below what you could complete with proper form—unless lifting to failure is that day's strategy.
The bottom line:
The more complicated the lift, the higher the risk of last-rep injuries since more muscles and bodily systems need to be engaged, Peterson says.
For extra precaution, move slowly and intentionally through each rep and use a heart rate monitor to keep you within 65 to 75 percent of your max, which ensures you're working efficiently and within your abilities.