Welcome to MythBusters, a Golf Digest+ series where we explore answers to some of golf’s most common questions through a series of tests with real golfers. While our findings might fall short of definitive, they still aim to shed new light on topics that have consumed golfers for years.
That Augusta National Golf Club has more elevation changes than what appears on TV is such a common observation that it has become cliché, but the truth still holds. At the 2025 Masters, players will face one of the most physically demanding walks of the entire year.
Which leads us to the question: How does fatigue affect the golf swing? As rounds progress and our bodies get more tired, do we start to swing slower or hit the ball more offline? We tested it.
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To learn more about how fatigue affects the golf swing, two Golf Digest staffers—Drew Powell (+2.4 Handicap Index) and Sam Weinman (11.4 Handicap Index)—hit a series of shots with a 9-iron and a driver when they were fully rested and after strenuous exercise.
Each player hit 10 shots with a 9-iron and 10 shots with a driver toward the beginning of their day when fully rested. Both Powell and Weinman wear a Whoop fitness tracker, and to verify that their bodies were not fatigued, each hit the shots when their daily strain (a measure of how exerted the body is) was less than 6.0, which is quite low.
Then, both players performed strenuous cardio workouts, similar to the exertion you experience during a round of golf. Powell and Weinman ensured their daily strain on their Whoop trackers surpassed 13.0, which is a typical amount of strain for a round of golf. After exercise, Powell and Weinman hit 10 shots with a 9-iron and 10 with a driver.
For all the shots, we measured swing speed, ball speed, carry distance and dispersion.
What we found 
Weinman’s clubhead speed, ball speed and carry distance all decreased with his fatigued swings with both a 9-iron and a driver. His carry distance was about a yard shorter with a 9-iron with his fatigued swing, and with his driver, his tired swing traveled seven yards less.
In addition to hitting it shorter when he was tired, Weinman’s dispersion was significantly worse. He averaged more than 11 feet farther from the target with a 9-iron and 11 yards more offline with the driver.
Powell’s results were similar. His clubhead speed, ball speed and carry all decreased with his fatigued swings with both 9-iron and driver. With his tired swings with driver, Powell’s carry distance was four yards less, and his dispersion was slightly more offline as well. Interestingly, his dispersion with the 9-iron got about two yards closer to the target with his fatigued swings.
What it means
Powell and Weinman both show that fatigue can have a negative effect on clubhead speed, distance and often dispersion as well. There are a few reasons for this. First, both Powell and Weinman felt like their tired legs were much tougher to move properly through the ball. Since the lower body is responsible for much of the power in the downswing, when their legs are tired and don’t rotate quite as hard through the shot, distance can decrease.
Second, Powell and Weinman both felt that it was tougher to make a full shoulder turn in the backswing when they were tired versus when they were fresh. Less shoulder turn can contribute to a slower swing speed and an over-the-top downswing. Weinman felt that to be especially true with his fatigued shots, which tended to leak to the right with a weaker ball flight.
It’s worth noting, however, that the changes is distance were not incredibly significant. The greatest loss was Weinman with a driver, and even then, it was less than seven yards lost when he was fatigued. Our results show that distance does decrease with fatigue, but in Powell and Weinman’s case, not by a ton.
What it doesn’t mean
Fatigue affects each golfer’s swing in unique ways based on their swing tendencies. Everyone’s golf swing has different power sources, so if you’re someone who doesn’t use your legs as much in the swing, fatigue might affect you less than someone who relies on a powerful leg drive for power. Also, if you’re someone who tends to swing over-the-top in the downswing, you may find that fatigue causes you to make an even shorter backswing turn, further exacerbating a slice. This may not be an issue for someone who doesn’t fight a slice.
Verdict
Fatigue decreases clubhead speed, ball speed and carry distance, but in Powell and Weinman’s case, not by a significant amount. The losses were a few miles per hour and a few yards, but still, there were consistent losses for each player with each club. Fatigue also can cause a greater dispersion, with shots traveling more offline. We’ll see if these results translate at all to how tour pros will react come Sunday’s final round at the Masters.
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This article was originally published on golfdigest.com
