Strength training experts emphasize time under tension and controlled movement

Experts in fitness and longevity suggest that muscle development and strength gains depend on more than just increasing weight. Focusing on the speed of repetitions and time under tension can significantly enhance exercise effectiveness.

Medical expert Sebastián La Rosa emphasizes the importance of controlling the three phases of movement: concentric (muscle shortening), eccentric (muscle lengthening), and isometric (static hold). He notes that controlling the eccentric phase—the descent of a weight—can double the duration of a set, increasing muscle development without needing heavier loads.

Similarly, personal trainer Javier Abreu clarifies that the ‘burning sensation’ often felt during high-repetition, low-weight sets is a subjective indicator of local effort rather than a definitive measure of strength gains. While light loads can promote hypertrophy, he suggests that compound movements with higher loads, such as leg presses with fewer repetitions, can provide a more effective stimulus for strength without the intense muscular burning associated with high-repetition isolation exercises.