Effects of High-intensity Training and Electrical Stimulation on Pain, Disability, Knee Kinematic and Performance in Patellofemoral Pain: A Randomized Controlled Trial

Patellofemoral pain (PFP) is a widespread problem in athletes who participate in jumping, cutting, and pivoting sports. Forty-four players participated in this study. They were divided into two groups: exercise plus EMS (G1) and exercise without EMS (G2), both with 12 women and 10 men. The exercise performed was 8 weeks of a high-intensity strength program for 45-60 minutes, plus cooling and a warm-up phase. Visual analogue scale (VAS), disability (Kujala patellofemoral score), knee valgus angle (KVA) and single-leg hop (SLH) were tested before (pre-test) and after training (post-test at 8 weeks) using a within-between group analysis (ANOVA 2×2). At baseline, no differences between groups were found (p > 0.05). After the intervention, both groups improved VAS, KVA, SLH (p < 0.001), and disability (p = 0.042). G1 showed more improvements than G2 for VAS (- 63.4 vs - 51.5 %, p = 0.021, 𝜂p2 = 0.13), disability (+ 32.6 vs + 18.4 %, p = 0.001, 𝜂p2 = 0.52), KVA (+ 4.2 vs + 2.2 %, p = 0.016, 𝜂p2 = 0.214) and SLH (+ 12.3 vs + 6.0 %, p = 0.003, 𝜂p2 = 0.20) respectively. No differences were found between the sexes for each group. Despite both interventions being valid, high-intensity strength training combined with EMS improved pain, disability, knee kinematics, and lower extremity performance more than exercise alone in professional handball athletes with PFP. Keywords: Electrical muscle stimulation, Rehabilitation, Musculoskeletal, Knee, Handball players