Muscle Stretching: Exploring the Impact of Different Modalities on Maximal Range of Motion and Strength with...

Muscle stretching comprises various modalities that differ in methodological aspects and provide distinct acute and long-term effects on maximal range of motion (ROM_max) and muscle strength. This narrative review aims to: i) describe each stretching modality in detail, including current approaches to quantifying intensity and volume; ii) examine how variations in these parameters influence acute and chronic adaptations in ROM_max and strength; and iii) provide practical guidance by highlighting each method's advantages, limitations, and effectiveness in achieving flexibility improvements with minimal impact on strength. The reviewed modalities include passive or active static stretching, dynamic or ballistic stretching, and proprioceptive neuromuscular facilitation (PNF). Intensity is commonly measured as stretch-induced discomfort (static), movement velocity or frequency (dynamic/ballistic), or contraction effort (PNF). Volume is quantified as total time at a given %ROM_max (static), number of repetitions (dynamic/ballistic), or contraction-relaxation cycles (PNF). Passive static stretching is effective for increasing ROM_max but may transiently reduce maximal isometric strength, particularly with higher intensities and durations. Dynamic stretching improves ROM_max without affecting strength, while ballistic stretching carries a greater risk of strength impairment. PNF techniques enhance ROM_max across intensity levels, and modified protocols may reduce associated discomfort. Long-term stretching interventions improve flexibility without negatively impacting strength, supporting their strategic use in training. Static stretching may even produce small strength gains when sustained for at least eight weeks. While all modalities acutely enhance ROM_max, chronic effects vary depending on protocol design. Selecting an appropriate stretching technique should align with specific performance goals, particularly in sports requiring extreme ROM_max or when combined with resistance training. Practical considerations such as safety, control, and participant familiarity are essential for effective long-term program implementation.