Acute Effects of Tissue Flossing Around the Upper Thigh on Neuromuscular Performance: A Study Using Different Degrees of Wrapping Pressure.

CONTEXT: It has been recently demonstrated that tissue flossing around the ankle joint can be effectively used to improve ankle range of motion, jump, and sprint ability. However, there is a lack of studies investigating the acute effects of tissue flossing applied using different wrapping pressures. OBJECTIVE: To investigate the acute effects of tissue flossing and the degree of floss band pressure, around the upper thigh on knee range of motion, strength, and muscle contractile characteristics. DESIGN: Crossover design in 3 distinct sessions. SETTING: University laboratory. PARTICIPANTS: A total of 19 recreationally trained volunteers (age 23.8[4.8] y) participated in this study. INTERVENTION: Active knee extension and flexion performed for 3 sets of 2 minutes (2-min rest between sets with wrapped upper thigh). Individualized wrapping pressures were applied to create conditions of high and moderate vascular occlusion, while a loose band application served as a control condition. MAIN OUTCOME MEASURES: Participants were assessed for active straight leg raise test; tensiomyography displacement and contraction time for rectus femoris, vastus medialis, and biceps femoris muscles; and maximum voluntary contractions for knee extensors and flexors for pre, after, and 30 minutes after applying the floss band. RESULTS: There was a statistically significant increase in maximum voluntary contractions for knee extensors and a significant shortening in rectus femoris contraction time for the moderate condition, which was associated with small to medium effects in favor of the moderate condition. There were no statistically significant changes observed between control and high conditions. The active straight leg raise test was unaffected regardless of intervention. CONCLUSIONS: The results of this study suggest that tissue flossing around the upper thigh might have a localized as well as pressure-sensitive response, thereby improving neuromuscular function of the knee extensors.

Use of Near-Infrared Spectroscopy to Measure Tissue Oxygen Saturation During Total Knee Arthroplasty With Use of a Tourniquet.

The primary purpose of this proof-of-concept quality improvement effort was to evaluate the practicality of using near-infrared spectroscopy (NIRS) to measure tissue oxygen saturation (Sto2) during total knee arthroplasty (TKA) with use of a tourniquet. NIRS sensors were applied to the biceps femoris (BF) and gastrocnemius (GS) muscles of both lower extremities of patients undergoing TKA procedures. For a convenience sample of 15 patients, measurement of Sto2 was attempted at baseline, following subarachnoid block administration, and after tourniquet inflation and deflation. Mean baseline Sto2 (SD) was 71% (6%) in the BF muscle and 66% (7%) in the GS muscle. Significant changes in Sto2 values were observed following subarachnoid block, tourniquet inflation, and tourniquet deflation. The Sto2 returned to or above baseline in the BF muscle but did not return to baseline in the GS muscle following tourniquet deflation. Changes in tissue oxygen saturation resulting from use of a tourniquet can be continuously monitored with the use of an NIRS device. Further evaluation of the use of NIRS should be undertaken to determine if it could be used to guide safe duration and pressure limits for tourniquet inflation.

Blood Flow-Restricted Training for Lower Extremity Muscle Weakness due to Knee Pathology: A Systematic Review.

CONTEXT:: Blood flow-restricted training (BFRT) has been suggested to treat lower extremity muscle weakness. The efficacy of BFRT for muscle problems related to knee pathology is unclear. OBJECTIVE:: To determine whether BFRT (1) improves muscle strength and cross-sectional area (CSA) for chronic knee-related lower extremity atrophy and (2) prevents muscle atrophy after knee surgery. DATA SOURCES:: A systematic review of the literature from 1974 to 2017 was conducted using the PubMed and Cochrane databases. STUDY SELECTION:: Controlled trials that used BFRT to treat chronic knee-related lower extremity muscle atrophy or to prevent muscle atrophy after knee surgery that measured the effects on quadriceps or hamstrings muscle strength or CSA were included. STUDY DESIGN:: Systematic review. LEVEL OF EVIDENCE:: Level 2. DATA EXTRACTION:: Data were extracted as available from 9 studies (8 level 1, 1 level 2). Assessment of study quality was rated using the Physiotherapy Evidence Database or Methodological Index for Non-Randomized Studies instruments. RESULTS:: BFRT was used after anterior cruciate ligament reconstruction and routine knee arthroscopy and in patients with knee osteoarthritis or patellofemoral pain. There were a total of 165 patients and 170 controls. Vascular occlusion and exercise protocols varied; all studies except 1 incorporated exercises during occlusion, most of which focused on the quadriceps. Six of 7 studies that measured quadriceps strength reported statistically significant improvements after training. Few benefits in quadriceps CSA were reported. Hamstrings strength was only measured in 2 studies. There were no complications related to training. CONCLUSION:: Published limited data show BFRT to be safe and potentially effective in improving quadriceps muscle strength in patients with weakness and atrophy related to knee pathology. The use of short-duration vascular occlusion and light-load resistance exercises appears safe after knee surgery or in arthritic knees. This treatment option requires further investigation to refine protocols related to cuff pressure and exercise dosage and duration.

Hemorheological alterations following an acute bout of nordic hamstring exercise in active male participants1.

BACKGROUND: The Nordic hamstring exercise (NHE) has been proven to be an effective preventive technique for hamstring injuries. Hemorheological parameters (erythrocyte deformability and aggregation) play a critical role in exercise influencing oxygenation. Although previous studies presented hemorheological alterations induced by different types of exercise, changes in red blood cell (RBC) deformability and aggregation following NHE remain unknown. Present study was designed to explore possible alterations in hemorheological and oxidative parameters after an acute bout of NHE. METHODS: 10 healthy, male, active students (mean age 19.9±0.23, BMI: 21.56±0.54) participated to the study. They performed a single session of seven-repetitions of NHE followed by a familiarisation period. Blood samples were obtained before and immediately after the exercise from the antecubital vein. Hemorheological parameters were measured by an ektacytometer. RESULTS: NHE did not change deformability, hematocrit and oxidative stress but, increased RBC aggregation index (AI, p = 0.011) and decreased RBC aggregation half time (t½, p = 0.009). CONCLUSIONS: Our results suggest that, increased RBC aggregation following an acute bout of NHE may result in increased plasma skimming and thus ease the flow of blood.

* Skeletal Myoblast-Seeded Vascularized Tissue Scaffolds in the Treatment of a Large Volumetric Muscle Defect in the Rat Biceps Femoris Muscle.

High velocity impact injuries can often result in loss of large skeletal muscle mass, creating defects devoid of matrix, cells, and vasculature. Functional regeneration within these regions of large volumetric muscle loss (VML) continues to be a significant clinical challenge. Large cell-seeded, space-filling tissue-engineered constructs that may augment regeneration require adequate vascularization to maintain cell viability. However, the long-term effect of improved vascularization and the effect of addition of myoblasts to vascularized constructs have not been determined in large VMLs. Here, our objective was to create a new VML model, consisting of a full-thickness, single muscle defect, in the rat biceps femoris muscle, and evaluate the ability of myoblast-seeded vascularized collagen hydrogel constructs to augment VML regeneration. Adipose-derived microvessels were cultured with or without myoblasts to form vascular networks within collagen constructs. In the animal model, the VML injury was created in the left hind limb, and treated with the harvested autograft itself, constructs with microvessel fragments (MVF) only, constructs with microvessels and myoblasts (MVF+Myoblasts), or left empty. We evaluated the formation of vascular networks in vitro by light microscopy, and the capacity of vascularized constructs to augment early revascularization and muscle regeneration in the VML using perfusion angiography and creatine kinase activity, respectively. Myoblasts (Pax7+) were able to differentiate into myotubes (sarcomeric myosin MF20+) in vitro. The MVF+Myoblast group showed longer and more branched microvascular networks than the MVF group in vitro, but showed similar overall defect site vascular volumes at 2 weeks postimplantation by microcomputed tomography angiography. However, a larger number of small-diameter vessels were observed in the vascularized construct-treated groups. Yet, both vascularized implant groups showed primarily fibrotic tissue with adipose infiltration, poor maintenance of tissue volume within the VML, and little muscle regeneration. These data suggest that while vascularization may play an important supportive role, other factors besides adequate vascularity may determine the fate of regenerating volumetric muscle defects.

Three-layered architecture of the popliteal fascia that acts as a kinetic retinaculum for the hamstring muscles.

When patients report pain in the popliteal fossa upon knee extension, the pain is usually localized in the lower region of the popliteal fossa. However, some patients complain of pain in the upper region of the popliteal fossa as the knee is flexed, which motivated us to examine the role of the popliteal fascia as the retinaculum of the hamstring muscles. Thirty-four thighs from 19 Japanese cadavers were dissected. The popliteal fascia was defined as the single aponeurotic sheet covering the popliteal fossa. We found that the fascia acted as a three-layered retinaculum for the flexor muscles of the thigh and provided a secure route for neurovascular structures to the lower leg in any kinetic position of the knee joint. The superficial layer of the popliteal fascia covering the thigh was strongly interwoven with the epimysium of biceps femoris along its lateral aspect and with that of the semimembranosus along its medial aspect, ensuring that the flexor muscles remained in their correct positions. The intermediate layer arose from the medial side of biceps femoris and merged medially with the superficial layer. The profound layer stretched transversely between the biceps femoris and the semimembranosus. Moreover, we investigated the nerve distribution in the popliteal fascia using Sihler's staining and whole-mount immunostaining for neurofilaments. The three-layered fascia was constantly innervated by branches from the posterior femoral cutaneous or saphenous nerve. The nerves were closely related and distributed to densely packed collagen fibers in the superficial layer as free or encapsulated nerve endings, suggesting that the fascia is involved in pain in the upper region of the popliteal fossa.