How well do experts read other people?
Certified coaches misjudged how many repetitions a lifter had left by almost five early in a set, and experience barely helped.
Published: Sports Medicine – Open, 2022 (lead author)
Participants: 259 certified resistance-training coaches
Stimuli: Videos of 8 trainees lifting to failure: squats and preacher curls at 70% or 80% of maximum
Measure: Predicted repetitions left at 33%, 66% and 90% of each set
The question
Coaches adjust training by watching how hard a set looks. We tested how accurate that judgment is.
What we did
Each coach watched a video of a trainee lifting to failure and predicted how many repetitions were left at three points in the set. We compared every prediction with what actually happened, and separated systematic bias (predicting too few or too many) from imprecision (how far off, in either direction).
What we found
Coaches underestimated early in the set and slightly overestimated near the end. Predictions were more accurate for heavier loads, for second sets, and for curls than for squats. Years of coaching experience barely improved accuracy.
What it shows
Experienced people’s intuitions about others are valuable, and they are biased in predictable places. Measuring the gap between what a team expects and what users actually do is often the quickest way to move a discussion from opinion to evidence.
Read the paper: Seeing effort: Assessing coaches’ prediction of the number of repetitions in reserve before task failure (Sports Medicine – Open, 2022).
