After five weeks of strength training using either light or heavy effort levels, people show less stability in their muscle force during sustained, moderate-intensity contractions as they become...

We analyzed the available evidence and found that resistance training, whether done with low or high effort, is associated with a reduction in torque steadiness during fatigue. After five weeks of training using either light or heavy loads, people showed less stability in their ability to maintain consistent muscle force during sustained, moderate-intensity contractions as they became tired [1]. The level of effort used during training — whether close to failure or not — did not change how much this steadiness declined [1]. Torque steadiness refers to how smoothly and consistently a muscle can hold a steady force over time. When this declines, movements become more shaky or uneven, especially as fatigue sets in. This pattern was observed regardless of whether the training was done with lighter weights and higher repetitions or heavier weights and lower repetitions. What we’ve found so far suggests that fatigue-related loss of force control may be a common outcome of resistance training, no matter how hard the effort. We did not find any evidence suggesting that one approach protects against this decline better than another. This doesn’t mean training is harmful — it’s a normal part of how muscles respond to repeated stress. But it does mean that, as you get tired during a workout or daily activity, your control over precise movements may become less smooth, regardless of how you trained. For everyday people, this means that even if you train hard or easy, you might notice your movements feel less steady when you’re tired. Slowing down, focusing on control, and allowing rest between efforts may help manage this effect.