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. Author manuscript; available in PMC: 2019 Jul 2.
Published in final edited form as: Am J Sports Med. 2017 Jul 31;46(6):1492–1499. doi: 10.1177/0363546517716930

TABLE 1.

Summary of Meta-analysis Evaluating the Effect of IPPs on Primary Biomechanical Variables Related to the Quadriceps and Ligament Dominance Theoriesa

Kinematic Variables No. of
Studies
Reference No. n Heterogeneity Test for
Overall Effect
Mean
Difference
95% CI Result
After IPP


P I2 Z P

Hip flexion at IC 4 8, 11, 18, 23   79 .22 30% 2.60 .009   4.21   1.04 to 7.38 Increased
Peak hip flexion 8 6, 8, 11, 12, 18, 23, 30, 48 173 .60   0% 3.14 .002   3.70   1.39 to 6.01 Increased
Hip adduction at IC 3 8, 23, 33   75 .19 37% 0.12 .90 –0.15 –2.60 to 2.30 No effect
Peak hip adduction 5 6, 8, 23, 33, 43 123 .15 35% 0.70 .48 –0.60 –2.27 to 1.07 No effect
Knee flexion at IC 6 8, 9, 11, 18, 23, 35 104 .08 47% 1.33 .18   1.83 –0.87 to 4.52 No effect
Peak knee flexion 13 6–9, 11, 12, 15, 18, 23, 25, 30, 43, 48 237 .15 28% 2.69 .007   2.86   0.78 to 4.95 Increased
Knee abduction at IC 5 3, 8, 11, 23, 33 108 .45   0% 0.60 .55 –0.25 –1.05 to 0.56 No effect
Peak knee abduction 11 3, 6, 8, 11, 12, 23, 30, 33, 43, 48, 51 239 .94   0% 0.75 .45 –0.29 –1.05 to 0.47 No effect

Kinematic Variables No. of
Studies
Reference No. n Heterogeneity Test for
Overall Effect
Standard
Mean Difference
95% CI Result
After IPP


P I2 Z P

Peak hip flexion moment 5 6, 8, 11, 18, 23 109 .31 15% 1.42 .16 –0.22 –0.51 to 0.08 No effect
Peak hip adduction moment 4 6, 8, 12, 23 126 .72   0% 0.48 .63   0.06 –0.19 to 0.31 No effect
Peak knee flexion moment 7 6, 8, 9, 11, 18, 23, 51 139 .76   0% 2.81 .005 –0.34 –0.58 to –0.10 Decreased
Peak knee abduction moment 12 3, 6–9, 11, 12, 23, 25, 32, 34, 51 260 .10 33% 2.44 .01 –0.28 –0.50 to –0.05 Decreased
Peak vGRF 10 1, 3, 8, 12, 15, 19, 23, 28, 31, 51 214 .02 49% 1.63 .10 –0.23 –0.51 to 0.05 No effect
a

Most forest plots are in Appendix D. IC, initial contact; IPP, injury prevention program; vGRF, vertical ground-reaction force.