Influence of external ankle support on lower extremity joint mechanics during drop landings

• Published in: Journal of sport rehabilitation 2010-05, Vol.19 (2), p.136-148
• Main Authors: Cordova, Mitchell L, Takahashi, Yosuke, Kress, Gregory M, Brucker, Jody B, Finch, Alfred E
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Ankle; Ankle Injuries - etiology; Ankle Injuries - prevention & control; Ankle Joint - physiology; Athletic Tape; Basketball - injuries; Basketball - physiology; Biomechanical Phenomena; Braces; Confidence Intervals; Cross-Over Studies; Deceleration; Hip Joint - physiology; Humans; Knee Joint - physiology; Lower Extremity - physiology; Male; Muscle Contraction - physiology; Muscle, Skeletal - physiology; Posture; Range of Motion, Articular; Risk Factors; Surveys and Questionnaires; Young Adult
• ISSN: 1056-6716; 1543-3072
• DOI: 10.1123/jsr.19.2.136

To investigate the effects of external ankle support (EAS) on lower extremity joint mechanics and vertical ground-reaction forces (VGRF) during drop landings. A 1 x 3 repeated-measures, crossover design. Biomechanics research laboratory. 13 male recreationally active basketball players (age 22.3 +/- 2.2 y, height 177.5 +/- 7.5 cm, mass 72.2 +/- 11.4 kg) free from lower extremity pathology for the 12 mo before the study. Subjects performed a 1-legged drop landing from a standardized height under 3 different ankle-support conditions. Hip, knee, and ankle angular displacement along with specific temporal (TGRFz1, TGRFz2; s) and spatial (GRFz1, GRFz2; body-weight units [BW]) characteristics of the VGRF vector were measured during a drop landing. The tape condition (1.08 +/- 0.09 BW) demonstrated less GRFz1 than the control (1.28 +/- 0.16 BW) and semirigid conditions (1.28 +/- 0.21 BW; P < .0001), and GRFz2 was unaffected. For TGRFz1, no-support displayed slower time (0.017 +/- 0.004 s) than the semirigid (0.014 +/- 0.001 s) and tape conditions (0.014 +/- 0.002 s; P < .05). For TGRFz2, no-support displayed slower time (0.054 +/- 0.006 s) than the semirigid (0.050 +/- 0.006 s) and tape conditions (0.045 +/- 0.004 s; P < .05). Semirigid bracing was slower than the tape condition, as well (P < .05). Ankle-joint displacement was less in the tape (34.6 degrees +/- 7.7 degrees) and semirigid (36.8 degrees +/- 9.3 degrees) conditions than in no-support (45.7 degrees +/- 7.3 degrees; P < .05). Knee-joint displacement was larger in the no-support (45.1 degrees +/- 9.0 degrees) than in the semirigid (42.6 degrees +/- 6.8 degrees; P < .05) condition. Tape support (43.8 degrees +/- 8.7 degrees) did not differ from the semirigid condition (P > .05). Hip angular displacement was not affected by EAS (F(2,24) = 1.47, P = .25). EAS reduces ankle- and knee-joint displacement, which appear to influence the spatial and temporal characteristics of GRFz1 during drop landings.