Thoracolumbar Fascia and Lumbar Muscle Stiffness in Athletes with A History of Hamstring Injury

Abstract

The purpose of this study was to examine the differences in thoracolumbar fascia (TLF) and lumbar muscle modulus in individuals with and without hamstring injury using shear wave elastography (SWE). Thirteen male soccer players without a previous hamstring injury and eleven players with a history of hamstring injury performed passive and active (submaximal) knee flexion efforts from 0°, 45° and 90° angle of knee flexion as well as an active prone trunk extension test. The elastic modulus of the TLF, the erector spinae (ES) and the multifidus (MF) was measured using ultrasound SWE simultaneously with the surface electromyography (EMG) signal of the ES and MF. The TLF SWE modulus was significantly (p < 0.05) higher in the injured group (range: 29.86 ± 8.58 to 66.57 ± 11.71 kPa) than in the uninjured group (range: 17.47 ± 9.37 to 47.03 ± 16.04 kPa). The ES and MF modulus ranged from 14.97 ± 4.10 to 66.57 ± 11.71 kPa in the injured group and it was significantly (p < .05) greater compared to the uninjured group (range: 11.65 ± 5.99 to 40.49 ± 12.35 kPa). TLF modulus was greater than ES and MF modulus (p < 0.05). Active modulus was greater during the prone trunk extension test compared to the knee flexion tests and it was greater in the knee flexion test at 0° than at 90° (p < 0.05). The muscle EMG was greater in the injured compared to the uninjured group in the passive tests only (p < 0.05). SWE modulus of the TLF and ES and MF was greater in soccer players with previous hamstring injury than uninjured players. Further research could establish whether exercises that target the paraspinal muscles and the lumbar fascia can assist in preventing individuals with a history of hamstring injury from sustaining a new injury.

Keywords: Biceps femoris strain; Spine; injured hamstring; myofascial.

Figure 1.

The experimental set-up. The ultrasound probe was placed 2.5 cm away from the L3 spinous process at the L3-L4 level to visualize the thoracolumbar fascia (TLF), the erector spinae (ES) and deep multifidus (MF). Bipolar electrodes were also placed on the ES and MF. TLF modulus was estimated by taking several circular regions of interest inside a rectangular coded box of 1.5. x 2 cm and ES and MF moduli were determined separately by drawing smaller circles within a 4 x 3 cm rectangular box. The color scale was extracted from the software and is enlarged so that the measurement scale is easily visible.

Figure 2.

Mean group passive SWE modulus values of thoracolumbar fascia (TLF), erector spinae (ES), multifidus (MF) values at knee flexion angles of 0, 45 and 90°. Error bars indicate standard deviation and circle dots are individual case values (* indicates statistically significant difference compared to the uninjured group; ^ values collapsed across angles and groups are statistically significant greater than ES and MF, p < .05).

Figure 3.

Mean group active SWE modulus values of thoracolumbar fascia (TLF), erector spinae (ES), multifidus (MF) values during submaximal contractions of the knee flexors at 0 (K0), 45 (K45) and 90° (K90) knee flexion angles and during prone trunk extension of 30° (TE). Error bars indicate standard deviation and circle dots are individual case values (* indicates statistically significant difference between groups, ^ values collapsed for groups and angles are greater compared to ES and MF values; # values collapsed for groups and tissues are greater compared to K0, K45 and K90; $ values collapsed for groups and tissues are greater than K90, p < 0.05).

Figure 4.

Maximum isometric torque values during knee flexion tests from at 0, 45 and 90° knee flexion angles. Error bars indicate standard deviation and circle dots are individual case values. * significant difference between groups; # torque, collapsed across groups, significantly different compared to 90°, p < 0.05.