Effects of isometric contraction of the quadriceps on the hardness and blood flow in the infrapatellar fat pad

Abstract

This study aimed to clarify the influence of the isometric contraction of the quadriceps (ICQ) with low intensity on the circulation in the infrapatellar fat pad (IFP). [Participants and Methods] The participants were 7 males and 5 females, with an average age of 21.5 ± 1.4 years. IFP hardness was measured using shear wave ultrasound elastography and Biodex. Tissue oxygenation was measured via near-infrared spectroscopy using oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) as indices. The mean values were calculated for three periods: 1 min of rest immediately before the exercise task (before ICQ), the lower limit of the 10 sets during the exercise task (during ICQ), and 3-4 min after the exercise task (after ICQ). IFP hardness was compared between resting conditions and ICQ, and tissue oxygenation was compared before, during, and after ICQ. [Results] ICQ significantly increased IFP hardness. Tissue hemoglobin, O2Hb, and cHb decreased significantly during ICQ and increased after ICQ compared to that before ICQ. HHb decreased during ICQ and recovered significantly after ICQ. [Conclusion] In healthy participants, low-intensity ICQ increases the hardness and oxygenation of the IFP. This study may partly explain the unknown pain relief mechanism of exercise therapy.

Effects of isometric loading intensity on patellar tendon microvascular response

“…However, this penetration depth would likely result in the deep fat pad, which has its own vascular supply, to be included in the measurement. Previous studies reported that, while this fat pad has a limited blood supply that may be accounted in the NIRS monitoring, its blood flow is minimally responsive to exercise 38 . Therefore, we feel confident our results truly represent the response of the tendons and the fad pad did not influence the final outcomes.…”

“…Previous studies reported that, while this fat pad has a limited blood supply that may be accounted in the NIRS monitoring, its blood flow is minimally responsive to exercise. 38 Therefore, we feel confident our results truly represent the response of the tendons and the fad pad did not influence the final outcomes. Additionally, the NIRS set-up used in the present study is unable to differentiate between changes in blood flow of the tendon and skin.…”

Validation of anterior ankle soft tissue dynamics and shear modulus for anterior ankle impingement syndrome after ankle fracture surgery

“…Kitagawa et al 17 evaluated the IFP thickness change ratio in anterior cruciate ligament (ACL)-reconstructed knees at 90° and 10° of knee flexion and defined the thickness change ratio as dynamic. Katayama et al 18 measured the IFP’s shear modulus in healthy adults using shear-wave elastography and evaluated IFP stiffness. In addition, Satake et al 19 reported that they observed a percentage of maximal fibrosis to increase as the shear wave speed of IFP increased.…”