| Witvrouw et al31 | Witvrouw et al32 | Herrington et al46 | |
| Type of study | Randomised controlled trial | Randomised controlled trial | Randomised controlled trial |
| Groups | 60 PFPS patients randomly allocated into either OKC (n = 30) or CKC (n = 30) exercise group | 60 PFPS patients randomly allocated into either OKC (n = 30) or CKC (n = 30) exercise group | 45 male PFPS patients randomly allocated into 1 of 3 groups:Group 1—non-weight bearing single joint exercises (n = 15)Group 2—weight bearing multiple joint exercise (n = 15)Group 3—control, no treatment group (n = 15) |
| Treatment | (1) Maximal static quadriceps muscle contractions | (1) Maximal static quadriceps muscle contractions | Knee extension exercise in sitting position (resistance and number of sets and repetitions calculated daily based on an adjustable progressive resistive exercise technique for each participant) |
| (2) SLR in supine | (2) SLR in supine | ||
| (3) Inner range quads exercises | (3) Inner range quads exercises | ||
| (4) Leg adduction exercises in the lateral decubitus position | (4) Leg adduction exercises in the lateral decubitus position | ||
| 3 sets of 10 repetitions, isometric contraction held for 6 s with a 3 s rest in between | 3 sets of 10 repetitions, isometric contraction held for 6 s with a 3 s rest in between | ||
| (1) Seated leg presses | (1) Seated leg presses | Seated leg press (resistance and number of sets and repetitions calculated daily based on an adjustable progressive resistive exercise technique for each participant) | |
| (2) One third knee bends on one and both legs | (2) One third knee bends on one and both legs | ||
| (3) Stationary bicycling | (3) Stationary bicycling | ||
| (4) Rowing machine | (4) Rowing machine | ||
| (5) Step-up/step-down exercises | (5) Step-up/step-down exercises | ||
| (6) Programme of jumping exercises | (6) Programme of jumping exercises | ||
| 3 sets of 10 repetitions | 3 sets of 10 repetitions, 3 s rest between repetitions | ||
| Outcome measures | 18 VAS scores—at rest and on various activities Kujala scoring scale 0–100 | 18 VAS scores—at rest and on various activities | Modified Kujala Questionnaire—pain level (ranging from 0–100) during stair climbing, squatting, running, jumping, and prolonged sitting. The presence of limp, swelling, subluxation, muscle atrophy examined as well as knee ROM deficits and the need for support when walkingVAS on step-up/step-downKnee extension strengthMeasured at start and after 6 weeks rehabilitation |
| Functional outcome measures | Functional outcome measures | ||
| Muscle strength | Muscle strength | ||
| Muscle length | Muscle length | ||
| Measurements taken before and after treatment, and after 3 months | Measurements taken before and after treatment and again after 5 years | ||
| Results | Both groups experienced a significant decrease in pain and an increase in functional performance. CKC group received significantly better functional results in some of the VAS scores which were not found in the OKC group. In CKC group, a significant increase in jumping distance was noted; however no significant increase noted in OKC group | At 5 year follow-up, both groups demonstrated maintenance of good subjective and functional outcomes achieved after the treatmentNo significant difference was noted between groups on most parameters examinedOn 3 of the 18 VAS recordings, the OKC group showed significantly fewer complaints compared to CKC group | Subjects in both groups showed a statistically significant decrease in pain and an increase in strength and functional performance when compared with the control group. No significant differences were seen between the 2 exercise groups. |
| PEDro score | 6/10 | 7/10 | 6/10 |
CKC, closed kinetic chain; OKC, open kinetic chain; PFPS, patellofemoral pain syndrome; ROM, range of movement; SLR, straight leg raise; VAS, visual analogue scale.