I was interested to read the manuscript by Lee and colleagues evaluating the effects of static and dynamic stretching in patients with patellofemoral pain who have inflexible hamstrings, as this is a common presentation of patients with knee pain. Although the benefits of dynamic stretching vs. static stretching have been extensively documented, this randomized controlled trial sheds light on the specific benefits of dynamic stretching for improving muscle activation time and clinical outcomes in this patient population. The investigators found that both static and dynamic stretching improved flexibility of the body’s hardware (muscles), but only dynamic stretching trained the body’s software (nervous system). Dynamic stretching trains the nervous system to enhance control of the musculoskeletal system for improved performance and reduced risk of injury.

One limitation of this study is the absence of a healthy control group; thus, a further prospective study is necessary to confirm differences in hamstring flexibility, knee muscle strength and muscle activation time between patients with patellofemoral pain and healthy asymptomatic controls. Furthermore, trunk and hip muscle activation and strength were not evaluated in this study. However, the investigators did include a core muscle-strengthening program and balance exercises to improve proprioception and neuromuscular control. Further investigations should include other stretching methods, such as proprioceptive neuromuscular facilitation and oscillation techniques, and to correlate the interventions with other objective measures of neuromuscular control such as electromyographic and biomechanical analysis. This information will help identify the most effective exercises for optimal muscle activation strategies to minimize pain and risk of injury throughout the kinetic chain.