Time course of the ground reaction force during the propulsion phase of the single leg hop test (SLHT).

<p>Fz(t) – normalized vertical ground reaction force; IPP – initial propulsion phase; EPP – end propulsion phase; TP – duration of the propulsion phase; PKFa – Peak Knee Flexion Angle; G – gravitational force acting on the human body (G = m.g, where m is the mass of the subject and g is the gravitational acceleration).</p

Characteristics of groups.

<p>Data expressed as mean (standard deviation). Abbreviations: VAS =  Visual analog scale; AKPS =  anterior knee pain scale.</p

Subject instrumentation.

<p>1. Electromyography (EMG) – electrode placement and subjects performed a maximum voluntary isometric contraction (MVIC); 2. Kinematic – marker placement; 3. Kinetic; 4. Motion capture during SLTHT – EMG, Kinematic and Kinetic data were captured simultaneously; 5. The propulsion phase was analysed.</p

Comparison of kinematic data, peak joint angles (°), kinetic data, internal joint moments (Nm/Kg) and EMG data, eccentric phase muscle activation (% MVIC) between patellofemoral pain group and control group during propulsion phase for SLTHT.

<p>Data expressed as mean (standard deviation).</p><p>*Negative value: ipsilateral trunk lean. Abbreviations: SLTHT =  single-leg triple-hop test.</p

Surface electromyography during a maximum voluntary isometric contraction (MVIC).

<p>Positioning of the subjects performing a MVIC for the gluteus maximus (A), biceps femoris (B), gluteus medius (C) and vastus lateralis (D), against a fixed resistance.</p