Figure 1.
Schematic drawing of the experimental setup.
A: Experimental setup, B: Measurement system | 1: stopper, 2: falling weight, 3: pulley, 4: steel rope, 5: force transducer, 6: force plate, 7: visual cover, 8: linear potentiometer. Arrows indicate the direction of the force. Posterior-anterior tibial translation was assessed by two linear potentiometers (8) placed on the patella and the tibial tuberosity. A force transducer (5) was used to measure the force transmitted to the shank.
Figure 2.
EMG and tibial translation data from one representative subject.
EMG activity of biceps femoris and semitendinosus/semimembranosus as well as posterior-anterior tibial translation of one subject. In the figure, EMG data is rectified in order to visualize the different parts of the hamstring stretch reflex. The vertical bold line indicates the onset of posterior-anterior tibial translation. Three different time intervals were analyzed (20–40, 40–60 and 60–95 ms).
Figure 3.
Effect of fatigue on tibial translation (left) and reflex responses (middle and right).
Filled bars: Pre, open bars: Post, BF: biceps femoris, ST: semitendinosus/semimembranosus. Data are displayed as means ± standard error of the mean. * denotes a significant difference compared to the pre-measurement, *P≤0.05; **P≤0.01.
Table 1.
Force applied to the proximal shank of the dominant leg and EMG onset latencies before and after the fatigue protocol for men and women. In addition, weight-normalized isometric maximum voluntary torque (iMVT), weight-normalized rate of torque development (RTD0–50, 0–100, 0–200) of the hamstrings (H) and quadriceps (Q), MVT H/Q ratio and RTD H/Q ratios (RTD0–50, 0–100, 0–200 H/Q) for men and women.
Table 2.
Correlations between posterior-anterior tibial translation and strength parameters for all subjects.