Authors: Sumiaki Maeo, Thomas G Balshaw, Darren Z Nin...

INTRODUCTION

The hamstring muscles play a crucial role in sprint running but are also highly susceptible to strain injuries, particularly within the biceps femoris long head (BFlh). This study compared the adaptations in muscle size and strength of the knee flexors, as well as BFlh muscle and aponeurosis size, after two eccentrically focused knee flexion training regimes: Nordic hamstring training (NHT) vs lengthened state eccentric training (LSET, isoinertial weight stack resistance in an accentuated hip-flexed position) vs habitual activity (no training controls: CON).

METHODS

Forty-two healthy young males completed 34 sessions of NHT or LSET over 12 wk or served as CON ( n = 14/group). Magnetic resonance imaging-measured muscle volume of seven individual knee flexors and BFlh aponeurosis area, and maximum knee flexion torque during eccentric, concentric, and isometric contractions were assessed pre- and post-training.

RESULTS

LSET induced greater increases in hamstrings (+18% vs +11%) and BFlh (+19% vs +5%) muscle volumes and BFlh aponeurosis area (+9% vs +3%) than NHT (all P ≤ 0.001), with no changes after CON. There were distinctly different patterns of hypertrophy between the two training regimes, largely due to the functional role of the muscles; LSET was more effective for increasing the size of knee flexors that also extend the hip (2.2-fold vs NHT), whereas NHT increased the size of knee flexors that do not extend the hip (1.9-fold vs LSET; both P ≤ 0.001). Changes in maximum eccentric torque differed only between LSET and CON (+17% vs +4%; P = 0.009), with NHT (+11%) inbetween.

CONCLUSIONS

These results suggest that LSET is superior to NHT in inducing overall hamstrings and BFlh hypertrophy, potentially contributing to better sprint performance improvements and protection against hamstring strain injuries than NHT.

Topics: Humans; Male; Hamstring Muscles; Young Adult; Resistance Training; Hypertrophy; Magnetic Resonance Imaging; Muscle Strength; Torque; Knee; Adaptation, Physiological; Aponeurosis; Isometric Contraction; Adult

PubMed: 38857522
DOI: 10.1249/MSS.0000000000003490

Review

Authors: F H Willard, A Vleeming, M D Schuenke...

In this overview, new and existent material on the organization and composition of the thoracolumbar fascia (TLF) will be evaluated in respect to its anatomy, innervation biomechanics and clinical relevance. The integration of the passive connective tissues of the TLF and active muscular structures surrounding this structure are discussed, and the relevance of their mutual interactions in relation to low back and pelvic pain reviewed. The TLF is a girdling structure consisting of several aponeurotic and fascial layers that separates the paraspinal muscles from the muscles of the posterior abdominal wall. The superficial lamina of the posterior layer of the TLF (PLF) is dominated by the aponeuroses of the latissimus dorsi and the serratus posterior inferior. The deeper lamina of the PLF forms an encapsulating retinacular sheath around the paraspinal muscles. The middle layer of the TLF (MLF) appears to derive from an intermuscular septum that developmentally separates the epaxial from the hypaxial musculature. This septum forms during the fifth and sixth weeks of gestation. The paraspinal retinacular sheath (PRS) is in a key position to act as a 'hydraulic amplifier', assisting the paraspinal muscles in supporting the lumbosacral spine. This sheath forms a lumbar interfascial triangle (LIFT) with the MLF and PLF. Along the lateral border of the PRS, a raphe forms where the sheath meets the aponeurosis of the transversus abdominis. This lateral raphe is a thickened complex of dense connective tissue marked by the presence of the LIFT, and represents the junction of the hypaxial myofascial compartment (the abdominal muscles) with the paraspinal sheath of the epaxial muscles. The lateral raphe is in a position to distribute tension from the surrounding hypaxial and extremity muscles into the layers of the TLF. At the base of the lumbar spine all of the layers of the TLF fuse together into a thick composite that attaches firmly to the posterior superior iliac spine and the sacrotuberous ligament. This thoracolumbar composite (TLC) is in a position to assist in maintaining the integrity of the lower lumbar spine and the sacroiliac joint. The three-dimensional structure of the TLF and its caudally positioned composite will be analyzed in light of recent studies concerning the cellular organization of fascia, as well as its innervation. Finally, the concept of a TLC will be used to reassess biomechanical models of lumbopelvic stability, static posture and movement.

Topics: Biomechanical Phenomena; Dissection; Fascia; Histological Techniques; Humans; Low Back Pain; Lumbar Vertebrae; Models, Biological; Muscle, Skeletal; Thoracic Vertebrae

PubMed: 22630613
DOI: 10.1111/j.1469-7580.2012.01511.x

Review

Authors: Lawrence S Bass, Michael S Kaminer

BACKGROUND

The etiology of cellulite is unclear. Treatment of cellulite has targeted adipose tissue, dermis, and fibrous septae with varying degrees of success and durability of response.

OBJECTIVE

Results from clinical trials that target different anatomical aspects of cellulite can provide insights into the underlying pathophysiology of cellulite.

MATERIALS AND METHODS

A search of the PubMed database and ClinicalTrials.gov website was conducted to identify clinical trials that have investigated treatments for cellulite.

RESULTS

A lack of trial protocol standardization, objective means for quantification of improvement and reported cellulite severity, and short-term follow-up, as well as variation in assessment methods have made comparisons among efficacy studies challenging. However, the lack of durable efficacy and inconsistency seen in clinical results suggest that dermal or adipose tissue changes are not the primary etiologies of cellulite. Clinical studies targeting the collagen-rich fibrous septae in cellulite dimples through mechanical, surgical, or enzymatic approaches suggest that targeting fibrous septae is the strategy most likely to provide durable improvement of skin topography and the appearance of cellulite.

CONCLUSION

The etiology of cellulite has not been completely elucidated. However, there is compelling clinical evidence that fibrous septae play a central role in the pathophysiology of cellulite.

Topics: Aponeurosis; Buttocks; Cellulite; Clinical Trials as Topic; Extracorporeal Shockwave Therapy; Humans; Lipectomy; Massage; Microbial Collagenase; Muscle, Skeletal; Phototherapy; Radiofrequency Therapy; Skin; Skin Cream; Subcutaneous Fat; Thigh; Treatment Outcome

PubMed: 32976174
DOI: 10.1097/DSS.0000000000002388

Review

Authors: Helene M Langevin

The network of fasciae is an important part of the musculoskeletal system that is often overlooked. Fascia mobility, especially along shear planes separating muscles, is critical for musculoskeletal function and may play an important, but little studied, role in proprioception. Fasciae, especially the deep epimysium and aponeuroses, have recently been recognized as highly innervated with small diameter fibers that can transmit nociceptive signals, especially in the presence of inflammation. Patients with connective tissue hyper- and hypo-mobility disorders suffer in large number from musculoskeletal pain, and many have abnormal proprioception. The relationships among fascia mobility, proprioception, and myofascial pain are largely unstudied, but a better understanding of these areas could result in improved care for many patients with musculoskeletal pain.

PubMed: 34357040
DOI: 10.3390/life11070668

Review

Authors: G Nourissat, G Ciais, H Coudane...

UNLABELLED

Obesity is a major public health issue, as incidence is rising in all developed countries, although the proportion is lower in Europe than in the U.S. Over and above the metabolic consequences and increased risk of diabetes, cardiovascular pathology and certain forms of cancer, the present study focuses on osteoarticular risk, and in particular on pathologies manageable by arthroscopy. It also analyzes results and complications specific to arthroscopy in these indications. Meniscal and ligamentous pathologies of the knee, rotator-cuff pathology in the shoulder and tendon pathology in the elbow were not significantly elevated, although a trend emerged. In contrast, there was significant elevation of Achilles and plantar aponeurosis pathology. In terms of postoperative complications, thromboembolic risk was elevated, but there were not significantly more complications specific to arthroscopy. Finally, subjective results were comparable to those for non-obese patients.

LEVEL OF EVIDENCE

Review.

Topics: Achilles Tendon; Arthroscopy; Elbow Joint; Humans; Menisci, Tibial; Obesity; Rotator Cuff; Rotator Cuff Injuries; Tendinopathy; Tibial Meniscus Injuries

PubMed: 26552647
DOI: 10.1016/j.otsr.2015.09.001

Authors: J H HICKS

Topics: Fascia; Foot; Humans; Muscle, Skeletal

PubMed: 13129168
DOI: No ID Found