18/01/2025
Hot off the press 🔥
Tensor Fasciae Latae and Gluteus Maximus Muscles: Do They Contribute to Hip Abduction? 🤔
👉 The classic hip abductors include the gluteus medius (Gmed) and minimus (Gmin) muscles. They are innervated by the superior gluteal nerve (SGN). These muscle groups are highly important to function of the hip joint and are relevant for a stable stance and locomotion (https://pubmed.ncbi.nlm.nih.gov/19136181/, .hhttps://pubmed.ncbi.nlm.nih.gov/30182152/ hhttps://pubmed.ncbi.nlm.nih.gov/21212373/ https://pubmed.ncbi.nlm.nih.gov/21212373/, https://pubmed.ncbi.nlm.nih.gov/16255022/).
👉 Thus, good abductor strength is essential for locomotion without walking aids (https://pubmed.ncbi.nlm.nih.gov/15001980/). Furthermore, abductor function is crucial for more demanding movements such as fast walking, walking uphill, running, squatting, and climbing stairs (https://pubmed.ncbi.nlm.nih.gov/12127184/).
👉 The tensor fasciae latae (TFL) and the gluteus maximus (Gmax), innervated by the superior and inferior gluteal nerves (SGN/IGN), respectively, are located in immediate anatomical proximity. They are discussed to partially compensate for the function of the classic hip abductors. Nevertheless, the main function of the Gmax is extension and external rotation of the hip and the main function of the TFL is flexion of the hip and stretching of the fascia latae with stabilizing effect on the knee (https://pubmed.ncbi.nlm.nih.gov/22109658/).
📘 In a brand-new study, Hoch and colleagues (https://pubmed.ncbi.nlm.nih.gov/39733244/) intend to investigate the amount of abduction force generated by the TFL, the gluteus medius and minimus, and the Gmax. This knowledge may help to understand the compensatory mechanisms that occur when the hip abductors are insufficient. Specific training of these potentially compensating muscle groups can, therefore, be a decisive component in the treatment of patients with hip abductor insufficiency, for example, in the treatment and rehabilitation of patients with neurological diseases, regarding preparation (prehab) for patients undergoing hip surgery or in the case of already established irreversible weakness.
👫 Participants:
➡️ Ten healthy adults (5 males, 5 females) aged 22–29 years participated.
➡️ Exclusion criteria were a history of the lower extremity, hip, or lower back pain, resp. surgery, neuromuscular disorders and pregnancy.
💡 Experimental Setup:
➡️ Sequential nerve blocks were applied to weaken the TFL, Gmed/min, and Gmax muscles selectively.
➡️ Abduction forces were measured in the lateral decubitus position under three hip positions: 30° flexion, neutral, and 30° extension.
🦵 Muscle Weakness Induction:
➡️ Nerve blocks were confirmed via electromyography to ensure selective muscle paralysis.
📊 Data Collection:
➡️ Maximum voluntary isometric contractions (MVICs) were tested using a dynamometer.
➡️ Statistical significance was determined using one-way repeated measures ANOVA.
📈 Results:
✅ General Observations:
▶︎ Hip abduction force was highest when all muscles were intact and significantly reduced following muscle-specific nerve blocks.
✅ Tensor Fasciae Latae (TFL):
▶︎ TFL contributed to abduction force primarily in 30° flexion, reducing it by 15% after paralysis.
▶︎ Its role in neutral and extended positions was negligible (-6,2 -12%).
✅ Gluteus Medius and Minimus (Gmed/min):
▶︎ Gmed/min were the primary contributors to abduction, accounting for over 60% (61,5%-63,3%) of force across all positions.
▶︎ Paralysis resulted in a two-thirds reduction in abduction force, rendering some participants unable to complete tasks in certain positions.
✅ Gluteus Maximus (Gmax):
▶︎ Gmax contributed significantly to abduction, with force reductions ranging from 43% to 56% across positions after paralysis.
▶︎ It was especially relevant during hip flexion.
🔑 Conclusion
✅ TFL: TFL has a minor role in hip abduction, mainly during flexion. Its primary function remains hip flexion and stabilization.
✅ Gmed/min: These muscles are the dominant abductors and crucial for hip stability and locomotion.
✅ Gmax: Previously underestimated, Gmax emerged as a significant contributor to abduction, particularly in flexed positions. Strengthening Gmax may help compensate for hip abductor insufficiency.
⭕ Limitations:
▶︎ The study measured abduction in specific, static positions, limiting real-life applicability.
▶︎ Compensatory mechanisms for chronic muscle weakness were not evaluated due to the acute nature of nerve blocks.
▶︎ No differentiation between different parts of the specific muscles.
📸 Illustration: https://link.springer.com/chapter/10.1007/978-3-642-00897-9_2
