Heavy vs Moderate vs Light Loads
1RM refers to one-rep max — the most weight that can be successfully lifted for one rep in a particular exercise. This amount is commonly used as a baseline to assign training weights.
You do not need to, and shouldn’t, test your 1RM in each exercise. There are simple formulas based on training weights that will give you a good estimate, and the Fit For Golf App calculates it for you.
Not all loads create the same adaptations. Heavy (85 % + of 1RM), moderate (65–85 % of 1RM), and light (< 65 % of 1RM) training can all make positive progress, but the adaptations are not equal. Adding more reps with light weights, while capable of increasing muscle mass just as well as heavier strength training, will not be as effective for increasing strength and power. There are neural and structural reasons for this.
When comparing heavy, moderate, and light loads for their effect on muscle growth, it’s critical that proximity to failure is standardized, otherwise the sets could be of vastly different effort levels. A set of 5, 12, and 20 reps taken to roughly 1 rep in reserve (i.e. one more rep but no more would have been possible at the end of the set) will create a very similar hypertrophy stimulus for type IIa fibers. The key difference is that heavier loads emphasize neural adaptations much more strongly, which are especially valuable for golfers aiming to increase strength and power.
Lighter loads can match hypertrophy when effort is equal, but they don’t produce the same neural benefits and come with higher fatigue.
It also leads to greater post-workout fatigue that takes longer to recover from and shifts fibers toward a more endurance or slow-twitch profile. This is not ideal for explosive power, though it can support the goal of increasing type IIa fiber size.