Effects of interval training and a taper on cycling performance and isokinetic leg strength

The purpose of this study was to determine whether changes in isokinetic leg strength parallel changes in cycling performance during a six-week high-intensity aerobic interval training program and a subsequent two-week taper. Eleven male collegiate cyclists participated in one competitive cycling graded exercise test, four consecutive days of aerobic intervals (30 min @82.2 +/- 0.74% HRmax, 1:1 work:relief), and four continuous rides (1-2 hr @65-80% HRmax) weekly. Pedalling cadence during training was generally 70-80 rpm suggesting a knee joint velocity of approximately 210 degrees.sec-1. Cycling performance and peak isokinetic torque (TQpk) for knee flexors (HAM) and knee extensors (QUAD) @30, 120, 210, and 300 degrees.sec-1 were assessed before, every two weeks during, and each week for two weeks following six weeks of interval training. Performance increased significantly during training (15%) and increased further during the taper (8%). QUAD TQpk @30 and 120 degrees.sec-1 increased significantly during training and the taper. In contrast, QUAD TQpk @210 and 300 degrees.sec-1 and HAM TQpk for all velocities were not significantly elevated following training. Interestingly, QUAD TQpk @300 but not 210 degrees.sec-1 significantly increased during the taper. Data from this study demonstrates that high-intensity aerobic interval cycling can promote gains in QUAD strength which occur primarily at contraction velocities slower than those utilized during cycling training. Additionally, a two-week taper can produce significant improvements in cycling performance (8%) and QUAD strength (8-9%) at 30 and 120 degrees.sec-1, however, the time-courses for these improvements do not parallel one another.