THE STRAIN BEHAVIOR OF THE ANTERIOR CRUCIATE LIGAMENT DURING BICYCLING - AN IN-VIVO STUDY

Stationary bicycling is commonly prescribed after anterior cruciate li gament injury or reconstruction; however, the strains on the ligament or ligament graft during stationary bicycling remain unknown, In this study we measured ligament strain on eight patients who were candidate s for arthroscopic meniscectomy under local anesthesia, Six different riding conditions were evaluated: three power levels (75, 125, and 175 W), each of which was performed at two cadences (60 and 90 rpm), The peak ligament strain values ranged from 1.2% for the 175-W, 90-rpm, co ndition to 2.1% for the 125-W, 60-rpm, condition, No significant diffe rences were found in peak strain values due to changes in power level or cadence, Thus, the strain values were pooled across the six riding conditions tested, The mean peak strain value was 1.7%, a value that i s relatively low compared with other rehabilitation activities previou sly tested. These data suggest that knee rehabilitation programs can b e designed to include this selection of power and cadence levels witho ut significantly changing ligament strain values, Thus, stationary bic ycling is a rehabilitation exercise that permits the patient to increa se muscle activity by increasing the power level or decreasing the cad ence without subjecting the ligament or ligament graft to higher strai n values.