Slow Speed Resistance Training in young football players with anterior knee pain

Introduction. Anterior Knee Pain (AKP) is common among active, healthy young people. In many cases, the true cause of anterior knee pain may not be clear because knee joint is sensitive to small problems in alignment, activity, training, and overuse (2). In particular, pressure may pull the kneecap sideways in its groove, causing pain behind the kneecap. In teenagers, a number of factors may be involved, such as imbalance of thigh muscles, poor flexibility, incorrect alignment of the legs between the hips and the ankles, improper sports techniques or equipment, and overload. Usually, the suggested therapy is the interruption of training and matches with a resting period between 3 and 16 weeks (3), combined with ice and eventually anti-inflammatory non steroidal drugs. After the pain and swelling go down, it is possible to restart with exercises aimed to regain Range Of Motion (ROM), strength, power, endurance, speed, agility, and coordination. In this study we examine the effects of Low Speed Resistance Training (LSRT; 1) as a support for technical exercises of moderate intensity in young football players affected by AKP. Methods. Eighteen young football players of regional level (13±1 yrs; 60±1 kg; 170±7 cm; 20.8±2.0 kg/m2), 11 healthy (H) e 7 with AKP, were trained for 6 weeks (1 times a week) with a program that mixes low intensity technical exercises with one weekly LSRT strength session where all subjects executed only one natural weight all-out LSRT squat set (n° of repetitions per set = 10). The duration of every repetition (knee ROM = 0-80°) was 14 s (subdivided into 7 s of concentric and 7 s of eccentric actions). All subjects were tested before starting and at the end of the strengthening programme with: Squatting Jump (SJ), Counter Movement Jump (CMJ), and CMJ with monopodalic stance (CMJ Mono; right: R; left: L). During the entire programme, pain was evaluated by Numeric Rating Scale (NRS) at the end of every strengthening session and 24 hours post-training. Results. We found significant differences (P<0.05) in SJ between H and AKP football players NRS in H players was 1.5±1.8 after training and 0.4±0.3 24hours after training (P>0.05). In AKP players NRS was 3.1±3.4 after training and 1.3±2.4 24 hours after training (P<0.05). In vertical jump, in monopodalic stance (CMJ mono), AKP subjects didn’t obtain significant changes, but there were significant improvements in H people (+22% in R and +10% in L; both P<0.05). Conclusions. All-out LSRT squat set systematically used in this strengthening programme, allowed obtain significant improvements in young football players that before this study could not follow out a single football training session because of anterior knee pain. A significant decrease of anterior knee pain and a progressive improvement of jumping performances were observed during the days after the training. Based on these preliminary data, it is possible to suggest LSRT as a useful training method that allows young football players affected by anterior knee pain to early return to their physical and technical training sessions. This method can be proposed also as a useful preventive means against overtraining pathologies.