Vastus Lateralis Muscle Thickness Research Articles

Evaluating the between-day reliability and likelihood of change of a test battery incorporating vastus lateralis muscle thickness, ankle-brachial pressure index, maximal voluntary torque, and six-minute walk test in patients with claudication.

The study aims to evaluate the between-day reliability of a proposed test battery for patients with claudication that can be used for monitoring the effectiveness of exercise interventions and other therapeutic strategies tailored to this patient population. Twenty-five men with claudication were recruited. The test battery consisted of the Vastus Lateralis muscle thickness (VL-MT), ankle-brachial pressure index (ABI), unilateral isometric knee extension maximal voluntary torque (MVT) and 6-minute walk test (6MWT). A single investigator conducted the tests for each patient on two separate testing sessions (T1 and T2) 5-7days apart. Good to excellent reliability was observed for VL-MT (ICC = 0.95, 95% LOA = ±3.10mm, SEM = 0.81mm), ABI (ICC = 0.97, 95% LOA = ±0.10, SEM = 0.02), MVT (ICC = 0.97, 95% LOA = ±24.0N·m, SEM = 6.31N·m), 6MWT distance (ICC = 0.99, 95% LOA = ±39.6m, SEM = 11.0m), 6MWT time to claudication (ICC = 0.99, 95% LOA = ±30.8s, SEM = 7.8s), and 6MWT ratings of pain (ICC = 0.87, 95% LOA = ±2.4 CR-10+, SEM = 0.7 CR-10+ ). Analysis derived from reliability data indicates a change of 1.4mm for VL-MT, 0.14 for ABI, 12N·m for MVT, 25m for 6MWT distance, 15s for 6MWT time to claudication and 1 CR-10+ for 6MWT ratings of pain is required to be interpreted as the minimum 'likely' change (76% chance). The test battery provides a reliable assessment of patients with claudication and can be widely used to evaluate the effects of exercise programmes and other therapeutic interventions. For the individual, changes in VL-MT, ABI, MVT, and 6MWT greater than the minimum likely change as a result of an exercise programme or an intervention are likely changes and less influenced by error associated with the test.

The influence of immobility on muscle loss in older people with frailty and fragility fractures.

This longitudinal study aimed to assess muscle morphological and functional changes in older patients admitted with fragility fractures managed by immobilisation of the affected limb for at least 6weeks. Patients aged ≥ 70 hospitalised with non-weight bearing limb fractures, and functionally limited to transfers only, were recruited. Handgrip (HGS) and knee extensor strength (KES), Vastus Lateralis muscle thickness (VLMT) and cross-sectional area at ultrasound (VLCSA) were measured in the non-injured limb at hospital admission, 1, 3 and 6weeks later. Barthel Index, mobility aid use and residential status were recorded at baseline and 16weeks. Longitudinal changes in muscle measurements were analysed using one-way repeated measures ANOVA. In a sub-study, female patients' baseline measurements were compared to 11 healthy, female, non-frail, non-hospitalised control volunteers (HC) with comparable BMI, aged ≥ 70, using independent t tests. Fifty patients (44 female) participated. Neither muscle strength nor muscle size changed over a 6-week immobilisation. Dependency increased significantly from pre-fracture to 16weeks. At baseline, the patient subgroup was weaker (HGS 9.2 ± 4.7kg vs. 19.9 ± 5.8kg, p < 0.001; KES 4.5 ± 1.5kg vs. 7.8 ± 1.3kg, p < 0.001) and had lower muscle size (VLMT 1.38 ± 0.47cm vs. 1.75 ± 0.30cm, p = 0.02; VLCSA 8.92 ± 4.37 cm2 vs. 13.35 ± 3.97 cm2, p = 0.005) than HC. The associations with lower muscle strength measures but not muscle size remained statistically significant after adjustment for age. Patients with non-weight bearing fractures were weaker than HC even after accounting for age differences. Although functional dependency increased after fracture, this was not related to muscle mass or strength loss, which remained unchanged.

The role of pennation angle and architectural gearing to rate of force development in dynamic and isometric muscle contractions.

Associations between muscle architecture and rate of force development (RFD) have been largely studied during fixed-end (isometric) contractions. Fixed-end contractions may, however, limit muscle shape changes and thus alter the relationship between muscle architecture an RFD. We compared the correlation between muscle architecture and architectural gearing and knee extensor RFD when assessed during dynamic versus fixed-end contractions. Twenty-two recreationally active male runners performed dynamic knee extensions at constant acceleration (2000°s-2) and isometric contractions at a fixed knee joint angle (fixed-end contractions). Torque, RFD, vastus lateralis muscle thickness, and fascicle dynamics were compared during 0-75 and 75-150 ms after contraction onset. Resting fascicle angle was moderately and positively correlated with RFD during fixed-end contractions (r = 0.42 and 0.46 from 0-75 and 75-150 ms, respectively; p < 0.05), while more strongly (p < 0.05) correlated with RFD during dynamic contractions (r = 0.69 and 0.73 at 0-75 and 75-150 ms, respectively; p < 0.05). Resting fascicle angle was (very) strongly correlated with architectural gearing (r = 0.51 and 0.73 at 0-75 ms and 0.50 and 0.70 at 75-150 ms; p < 0.05), with gearing in turn also being moderately to strongly correlated with RFD in both contraction conditions (r = 0.38-0.68). Resting fascicle angle was positively correlated with RFD, with a stronger relationship observed in dynamic than isometric contraction conditions. The stronger relationships observed during dynamic muscle actions likely result from different restrictions on the acute changes in muscle shape and architectural gearing imposed by isometric versus dynamic muscle contractions.

Lower limb muscles’ thicknesses are weakly associated with dynamic knee valgus during single-leg squat in women with patellofemoral pain

IntroductionPatellofemoral pain (PFP) patients often show an altered lower limb alignment during the single-leg squat (SLS). There is evidence that proximal and distal-to-the-knee muscle alterations can modify the lower limb alignment in PFP patients. However, we observed a lack of studies investigating the possible association between the thickness and strength of proximal and distal-to-the-knee muscles and lower limb alignment during SLS in women with PFP. Therefore, this study aimed to investigate the association between the thickness and strength of lower limb muscles and dynamic knee valgus (DKV) during SLS in women with PFP. MethodsCross-sectional study, where fifty-five women with PFP were submitted to the following evaluations: (1) muscle thickness (MT) of Gluteus Medius (GMed), Gluteus Maximus (GMax), Vastus Lateralis (VL), and Tibialis Anterior (TA); (2) isometric peak torque of hip abductors, hip external rotators, knee extensors, and foot inversors; and (3) DKV during SLS. ResultsThere was a significant negative association between GMax's MT and DKV (r = −0.32; p = 0.01), and between TA's MT and DKV (r = −0.28; p = 0.03). No significant correlations were observed between isometric torques and DKV. Regression analysis found that GMax's MT explained 10% of the DKV's variance during SLS. DiscussionPoor lower limb alignment during SLS is weakly associated with proximal and distal-to-the-knee muscle thicknesses, with no association with isometric torque in PFP women. ConclusionOur results suggest that other factors besides strength and muscle thicknesses may explain and improve lower limb alignment in women with PFP.

Changes in Lower Extremity Muscle Quantity and Quality in Patients with Subacute Stroke.

To analyze the changes in muscle mass and quality with time on the paretic and non-paretic sides in subacute stroke patients and identify correlations between the variation of muscle mass and quality and lower limb functions. Thirty hemiplegia patients diagnosed with stroke participated in this study. To evaluate poststroke muscle changes, longitudinal measurement of muscle mass and quality was conducted with bilateral lower limbs. The elastic shear modulus was measured using shear wave elastography and muscle thickness (MT) of rectus femoris, vastus intermedius, vastus lateralis (VL), vastus medialis, tibialis anterior, and gastrocnemius (GCM) muscles. Functional evaluation was performed using Berg Balance Scale (BBS), Five Times Sit to Stand Test (FTSST). Follow-up was performed at discharge. The muscle mass and quality were compared according to time. We analyzed whether muscle quantity and quality were related to function. MT demonstrated no significant change with time. The elastic shear modulus increased significantly in the paretic VL and GCM muscles and did not change significantly in the muscles on the non-paretic side. Correlation analysis detected that elastic shear modulus in the VL has a cross-sectional negative relationship between BBS and positive relationship between FTSST. There were significant correlation between variation of FTSST and the variation of the elastic shear modulus in VL. Only paretic VL and GCM muscle quality changed in subacute stroke patients and muscle's property related to lower limb functions. Therefore, the lower extremity requires an approach to muscle quality rather than quantity for subacute stroke patients.

Influences of Sex on Muscle Architecture and Performance in Elite Field Hockey Players

The aim of this study was to compare muscle architecture and performance between male and female elite Field Hockey players and to investigate the relationships between echo intensity and performance. Twenty-one male (24.3 ± 3.6 y; 75.1 ± 8.5 kg; 176.8 ± 6.4 cm) and nineteen female players (27.4 ± 3.9 y; 61.2 ± 7.4 kg; 164.4 ± 4.9 cm) were tested for muscle thickness (MT) and echo intensity (EI) of trapezius (Trap) and vastus lateralis (VL) muscles. Participants were also assessed for bench press power, and 30 m sprint. Results showed a higher VLMT and TrapMT in male players compared to female players (+22.1%; p = 0.004 and +25.8%; p = 0.001 for VLMT and TrapMT, respectively). A lower VLEI was detected in male players compared to female players (−20.7%; p = 0.001), while no significant differences were detected for TrapEI. Male players were faster than female players in a 30 m sprint and more powerful at the bench press (p &lt; 0.001). Significant correlations were detected between VLEI and 30 m sprint (r = 0.74) in female players only. Results indicate that differences exist between male and female elite Field Hockey players in the EI of lower body muscles, while these differences are not present in the upper body muscles. EI, together with other sprint and power assessments, may represent an important parameter for elite Field Hockey players.

Muscle Properties, Gross Motor Performance, and Quality of Life in Children With Sickle Cell Disease.

To explore muscle properties, gross motor performance, and quality of life (QoL) in children with sickle cell disease (SCD) compared with controls and to assess relationships among these outcomes. A cross-sectional study of 24 children assessed muscle properties including: knee extension strength by dynamometry; vastus lateralis (VL) and rectus femoris (RF) muscle thickness by ultrasonography; and VL and RF neuromuscular activation (rate of muscle activation [RoA]) by electromyography (EMG). Gross motor performance and QoL were assessed by standardized tests and questionnaires. Children with SCD had impaired knee extension strength, VL EMG RoA, gross motor performance, and QoL compared with children without SCD. Relationships among muscle properties, gross motor performance, and QoL were identified. These findings indicate that comprehensive muscle properties, gross motor performance, and QoL assessments should be considered to support and develop individualized physical therapy plans for children with SCD.

Factors Involved in Higher Knee Extension Torque Induced by Repetitive Peripheral Magnetic Stimulation.

The study aimed to determine the relationship between knee extension torque induced by repetitive peripheral magnetic stimulation and the characteristics of the participants. This was a basic study with noninvasive intervention. Knee extension torque induced by repetitive peripheral magnetic stimulation (repetitive peripheral magnetic stimulation-induced torque) and maximum voluntary contraction were measured. Stepwise method of multiple regression was performed to determine the factors affecting repetitive peripheral magnetic stimulation-induced torque at 100% intensity and repetitive peripheral magnetic stimulation-induced torque divided by maximum voluntary contraction (percent maximum voluntary contraction). Subcutaneous fat thickness, vastus lateralis muscle thickness measured by ultrasound, maximum voluntary contraction, and mean power frequency of electromyography during maximum voluntary contraction were selected as independent variables. Repetitive peripheral magnetic stimulation was applied to the right vastus lateralis of 30 young healthy adults (average age, 21.1 ± 0.3 yrs). In the multiple regression analysis, repetitive peripheral magnetic stimulation-induced torque ( P < 0.001) was shown to be independently and significantly associated with maximum voluntary contraction (β = 0.510), subcutaneous fat thickness (β = -0.358), and vastus lateralis muscle thickness (β = 0.208), while percent maximum voluntary contraction value ( P < 0.05) was independently and significantly associated with vastus lateralis muscle thickness (β = 1.059). Repetitive peripheral magnetic stimulation-induced torque decreases with thicker subcutaneous fat and increases with stronger maximum voluntary contraction or with thicker muscle.

Assessments of early patellofemoral joint osteoarthritis features after anterior cruciate ligament reconstruction: a cross-sectional study

BackgroundPersistent anterior knee pain and subsequent patellofemoral joint (PFJ) osteoarthritis (OA) are common symptoms after anterior cruciate ligament reconstruction (ACLR). Quadriceps weakness and atrophy is also common after ACLR. This can be contributed by arthrogenic muscle inhibition and disuse, caused by joint swelling, pain, and inflammation after surgery. With quadriceps atrophy and weakness are associated with PFJ pain, this can cause further disuse exacerbating muscle atrophy. Herein, this study aims to identify early changes in musculoskeletal, functional and quality of health parameters for knee OA after 5 years of ACLR.MethodsPatients treated with arthroscopically assisted single-bundle ACLR using hamstrings graft for more than 5 years were identified and recruited from our clinic registry. Those with persistent anterior knee pain were invited back for our follow-up study. For all participants, basic clinical demography and standard knee X-ray were taken. Likewise, clinical history, symptomatology, and physical examination were performed to confirm isolated PFJ pain. Outcome measures including leg quadriceps quality using ultrasound, functional performance using pressure mat and pain using self-reported questionnaires (KOOS, Kujala and IKDC) were assessed. Interobserver reproducibility was assessed by two reviewers.ResultsA total of 19 patients with unilateral injury who had undergone ACLR 5-years ago with persistent anterior knee pain participated in this present study. Toward the muscle quality, thinner vastus medialis and more stiffness in vastus lateralis were found in post-ACLR knees (p < 0.05). Functionally, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb with increasing knee flexion. In accordance, rectus femoris muscle stiffness in the ACLR knee was significantly correlated with pain (p < 0.05).ConclusionIn this study, it was found that patients having higher degree of anterior knee pain were associated with higher vastus medialis muscle stiffness and thinner vastus lateralis muscle thickness. Similarly, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb leading to an abnormal PFJ loading. Taken together, this current study helped to indicate that persistent quadriceps muscle weakness is potential contributing factor to the early development of PFJ pain.

Residual effects of 12 weeks of power-oriented resistance training plus high-intensity interval training on muscle dysfunction, systemic oxidative damage, and antioxidant capacity after 10 months of training cessation in older people with COPD.

This study aimed to assess the residual effects of a 12-week concurrent training program (power training + high-intensity interval training) in older adults with chronic obstructive pulmonary disease (COPD). A total of 21 older adults with COPD [intervention (INT), n = 8; control (CON), n = 13; 76.9 ± 6.8 years] were assessed at baseline and 10 months after the completion of the intervention by the short physical performance battery (SPPB), health-related quality of life (EQ-5D-5L), vastus lateralis muscle thickness (MT), peak pulmonary oxygen uptake (peak VO2 ) and peak work rate (Wpeak ), early and late isometric rate of force development (RFD), leg and chest press maximum muscle power (LPmax and CPmax ), and systemic oxidative damage and antioxidant capacity. Compared to baseline, after 10 months of detraining, the INT group presented increased SPPB (∆ = 1.0 point), health-related quality of life (∆ = 0.07 points), early RFD (∆ = 834 N∙s-1 ), LPmax (∆ = 62.2 W), and CPmax (∆ = 16.0 W) (all p < 0.05). In addition, a positive effect was noted in INT compared to CON regarding MT and Wpeak (both p < 0.05). No between-group differences were reported in peak VO2 , late RFD, systemic oxidative damage, and antioxidant capacity from baseline to 10 months after the completion of the intervention (all p > 0.05). Twelve weeks of concurrent training were enough to ensure improved physical function, health-related quality of life, early RFD and maximum muscle power and to preserve MT and Wpeak but not peak VO2 , late RFD, systemic oxidative damage and antioxidant capacity in the subsequent 10 months of detraining in older adults with COPD.

Muscle Architecture and Subcutaneous Fat Measurements of Rectus Femoris and Vastus Lateralis at Optimal Length Aided by a Novel Ultrasound Transducer Attachment.

Purpose: This cross-sectional study determines the sensitivity of muscle architecture and fat measurements of the rectus femoris (RF) and vastus lateralis (VL) muscles from ultrasound images acquired with varying transducer tilt, using a novel transducer attachment, in healthy adults. Secondary objectives were to estimate intrarater and interrater reliability of image measurement and acquisition, respectively. Methods: Thirty healthy adults participated (15 women and 15 men; 25 [SD 2.5] y). Ultrasound image acquisition was conducted by two raters at different transducer tilts relative to the skin: estimated perpendicular, and five measured angles (80°, 85°, 90°, 95°, 100°) using the transducer attachment. Muscle thickness (MT), subcutaneous fat thickness (FT), pennation angle (PA), and fascicle length (FL) were measured. Sensitivity and reliability were assessed using intra-class correlation coefficients (ICCs) and standard error of measurements (SEMs). Results: MT and FT for RF and VL were not sensitive to transducer tilt. However, PA and FL were sensitive to transducer tilt. MT and FT for both muscles showed high ICCs and low SEMs for intrarater and interrater reliability. For PA of both muscles, standardizing transducer tilt improved interrater ICCs and lowered SEMs. Conclusion: MT and FT measurements of RF and VL acquired at 60° knee flexion are robust to varying transducer tilt angles. PA measurements benefit from standardizing transducer tilt.

Collagen supplementation augments changes in patellar tendon properties in female soccer players.

We investigated the effect of collagen hydrolysate supplementation on changes in patellar tendon (PT) properties after 10weeks' training in female soccer players from a Football Association Women's Super League Under 21s squad. We pair-matched n = 17 players (age: 17 ± 0.9years; height: 1.66 ± 0.06m; mass: 58.8 ± 8.1kg) for baseline knee extension (KE) maximum isometric voluntary contraction (MIVC) torque, age, height, and body mass, and randomly assigned them to collagen (COL) or placebo (PLA) groups (COL n = 8, PLA n = 9). Participants consumed 30g collagen hydrolysate supplementation or energy-matched PLA (36.5g maltodextrin, 8.4g fructose) and plus both groups consumed 500mg vitamin C, after each training session, which comprised bodyweight strength-, plyometric- and/or pitch-based exercise 3 days/week for 10 weeks in-season. We assessed KE MIVC torque, vastus lateralis muscle thickness and PT properties using isokinetic dynamometry and ultrasonography before and after 10weeks' soccer training. KE MIVC torque, muscle thickness and tendon cross-sectional area did not change after training in either group. However, COL increased PT stiffness [COL, +18.0 ± 12.2% (d = 1.11) vs. PLA, +5.1 ± 10.4% (d = 0.23), p = 0.049] and Young's modulus [COL, +17.3 ± 11.9% (d = 1.21) vs. PLA, +4.8 ± 10.3% (d = 0.23), p = 0.035] more than PLA. Thus, 10weeks' in-season soccer training with COL increased PT mechanical and material properties more than soccer training alone in high-level female soccer players. Future studies should investigate if collagen hydrolysate supplementation can improve specific aspects of female soccer performance requiring rapid transference of force, and if it can help mitigate injury risk in this under-researched population.

Acute muscle swelling effects of a knee rehabilitation exercise performed with and without blood flow restriction.

This study assessed the acute effect of adding blood flow restriction (BFR) to quad sets on muscle-cross sectional area (mCSA), muscle thickness (MT), echo intensity (EI), and subcutaneous fat-normalized EI (EINORM) of the superficial quadriceps muscles. Twelve males and 12 females (mean±SD; age (yrs): 21.4±2.9; stature (m): 1.76±0.1; body mass (kg): 77.7±2.9) performed 70 repetitions (one set of 30, three sets of 15 repetitions) of bodyweight quad sets separately on each leg, with or without BFR (CON) applied. Rating of perceived exertion was recorded following each set. Panoramic ultrasound images of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) were captured prior to (PRE), immediately after (IMM-POST), 30- (30-POST), and 60-minutes after (60-POST) after exercise. Sex x condition x time repeated measures ANOVAs assessed differences at p<0.05 for each muscle and dependent variable separately. Although males had larger VM and VL mCSA and VL MT (p<0.05), there were no acute changes from PRE to IMM-POST (p>0.05). There was a 3-way interaction in VL mCSA (p = 0.025) which indicated BFR was greater than CON at IMM-POST by 7.6% (p = 0.019) for males only. Females had greater EI in the VM and VL than males (p<0.05), yet males had greater EINORM for each muscle (p>0.05) and EINORM did not change over time or treatment (p>0.05). The lack of changes in MT, EI, and EINORM indicate that unloaded quad sets do not provide a stimulus to promote fluid shifts or acute changes in muscle size with the exception of IMM-POST in the VL for males. Future research should attempt to elucidate the acute muscular responses of BFR application for lightly loaded rehabilitation exercises in the clinical populations for which they are prescribed.

Quantifying muscle strength, size, and neuromuscular activation in adolescent and young adult survivors of musculoskeletal sarcoma: Identifying correlates and responses to functional strengthening

BackgroundMedical and surgical treatment for musculoskeletal sarcoma (MSS) place survivors at risk for impairments in muscle properties including muscle strength, muscle size, and neuromuscular activation. The purpose of this study was to explore muscle properties, gross motor performance, and quality of life (QoL) and the changes in response to a 6-week functional strengthening intervention (PT-STRONG) in MSS survivors of childhood cancer (CCS). MethodsEight lower extremity MSS CCS (13–23 years old) performed baseline testing and three completed PT-STRONG. Participants completed measurements of knee extension strength using handheld dynamometry, vastus lateralis (VL) and rectus femoris (RF) muscle thickness using ultrasonography at rest, and neuromuscular activation using electromyography during strength testing and a step-up task. Participants also completed gross motor and QoL assessments. ResultsCompared with the non-surgical limb, MSS CCS had lower surgical limb knee extension strength, VL muscle thickness, and RF step-up muscle rate of activation (RoA). Compared with normative values, MSS CCS had decreased bilateral knee extension strength, gross motor performance, and physical QoL. Positive correlations among muscle strength, muscle thickness, and gross motor performance were identified. After PT-STRONG, MSS CCS had improvements in VL muscle thickness, VL and RF RoA duing step-up, gross motor performance, and physical QoL. ConclusionsPositive association between larger muscle thickness with greater knee extension strength, and higher knee extension strength with better gross motor performance indicate that comprehensive physical therapy assessment and interventions that identify and target impairments in muscle properties to guide clinical decision making should be considered for MSS CCS into survivorship.

Associations between Muscle-Tendon Morphology and Functional Movements Capacity, Flexibility, and Balance in Older Women.

Loss of functional movement capacity in older adults is related to adverse changes in musculotendinous morphology, but this relationship is poorly understood. This study examined the associations between musculotendinous morphology and functional movements, flexibility, and balance ability. Ninety-nine older women (66.6 ± 4.6 years, body mass index 23.5 ± 3.3 kg∙m−2) were recruited from Chonburi Province, Thailand. During one 90-min visit, muscle ultrasound imaging of vastus lateralis, biceps femoris, and medial gastrocnemius muscles, and tendon ultrasonography of the Achilles tendon and patellar tendon were performed. Measures were also obtained for the straight leg raise, passive dorsiflexion, balance, and functional tests (Five Times Sit to Stand (5TSTS), Timed Up and Go (TUG), 10-Meter Fast Walk Test (10-MFWT), and 6-Minute Walk Test (6-MWT)). The results specify that functional movement performance correlates most strongly with medial gastrocnemius muscle thickness (5TSTS (r = −0.26), TUG (r = −0.44), 10-MFWT (r = 0.41), and 6-MWT (r = 0.48) all p < 0.05) and that vastus lateralis muscle thickness and medial gastrocnemius muscle thickness correlate positively with balance ability (r = 0.24, 0.34; p < 0.05) and negatively with fear of falling. It appears that muscle mass, rather than other morphological parameters, such as muscle quality or fascicle length, is the main factor affecting the susceptibility of older women to frailty.

Differences in Knee Extensors' Muscle-Tendon Unit Passive Stiffness, Architecture, and Force Production in Competitive Cyclists Versus Runners.

To describe the possible effects of chronic specific exercise training, the present study compared the anthropometric variables, muscle-tendon unit (MTU) architecture, passive stiffness, and force production capacity between a group of competitive cyclists and runners. Twenty-seven competitive male cyclists (n = 16) and runners (n = 11) participated. B-mode ultrasound evaluation of the vastus lateralis muscle and patellar tendon as well as passive stiffness of the knee extensors MTU were assessed. The athletes then performed a test of knee extensor maximal voluntary isometric contractions. Cyclists displayed greater thigh girths, vastus lateralis pennation angle and muscle thickness, patellar tendon cross-sectional area, and MTU passive stiffness than runners (P < .05). Knee extensor force production capacity also differed significantly, with cyclists showing greater values compared with runners (P < .05). Overall, the direct comparison of these 2 populations revealed specific differences in the MTU, conceivably related to the chronic requirements imposed through the training for the different disciplines.

Acute effects of electrostimulation and blood flow restriction on muscle thickness and fatigue in the lower body

ABSTRACT Neuromuscular electrical stimulation (NMES) in combination with blood flow restriction (BFR) enhances muscle hypertrophy and force-generating capacity. The present study aimed to investigate the acute effects of BFR and NMES, both in isolation and in combination, on muscle thickness (MT) and fatigue in the lower body of 20 young healthy subjects. Different stimuli were applied for 25 min, defined by the combination of BFR with high- and low-frequency NMES, and also isolated BFR or NMES. Changes in MT were then evaluated by ultrasound of the rectus femoris (RF) and vastus lateralis (VL) muscles at the end of the session (POST) and 15 min later (POST 15’). Lower limb fatigue was evaluated indirectly by strength performance. Results showed that RF MT was higher under the combined protocol (BFR + NMES) or isolated BFR than under NMES – regardless of the frequency – both at POST (p ≤ 0.018) and POST 15’ (p ≤ 0.016). No significant changes in MT were observed under isolated NMES or BFR at POST 15’ when compared with basal values (p ≥ 0.067). No significant differences were observed for VL MT between conditions (p = 0.322) or for fatigue between conditions (p ≥ 0.258). Our results indicate that a combination of BFR and NMES acutely increases MT in sedentary subjects. Also, although not significantly, BFR conditions had a greater tendency to induce fatigue than isolated NMES. Highlights The combination of blood flow restriction (BFR) and neuromuscular electrical stimulation (NMES) produces higher acute cell swelling than the isolated application of either NMES or BFR. BFR in isolation appears to produce greater cell swelling than NMES, regardless of the frequency used. BFR conditions had a greater tendency to induce fatigue than isolated NMES.

Effect Of Proximity To Failure During Resistance Training On Vastus Lateralis Muscle Thickness

PURPOSE: To compare changes in muscle thickness at two sites (50% and 70%) of the vastus lateralis (VL50 MT, VL70 MT) between training programs with different proximities to failure using the repetitions in reserve (RIR)-based rating of perceived exertion (RPE) scale. METHODS: Fourteen males (height: 175.77 ± 5.72 cm, body mass: 80.15 ± 13.12 kg, squat one-repetition maximum-1RM relative to body mass: 1.72 ± 0.25) with ≥2 yrs of back squat experience were assigned to either 4-6 RPE, n = 7 (4-6 RIR) or 7-9 RPE, n = 7 (1-3 RIR) for 8wks. Ultrasonography was performed 48 hours before the first training session and 48 hours after the last session. Both groups performed the back squat 3x/wk on non-consecutive days (e.g., Mon., Wed., Fri.) using an undulating resistance training program, which decreased repetitions throughout. Weeks 1-3 consisted of 10, 8, and 6 repetitions on sessions 1, 2, and 3, respectively; weeks 4-5 consisted of 9, 7, and 5 repetitions; and weeks 6-7 consisted of 8, 6, and 4 repetitions. Week 1 was an introductory week in which fewer sets were performed at a lower RPE. Week 8 was a taper with 4 and 2 repetition days on session 1 and session 2, respectively, followed by post-testing in session 3. In weeks 2-7 (i.e., main training period), 10 weekly sets were performed for both the squat and bench press. Subjects were instructed to select a load in which the set ended with 4-6 RPE or 7-9 RPE. Equivalence testing and 90% confidence intervals were used to compare changes in VL50 MT and VL70 MT. Independent t-tests compared average intensity (% of 1RM) and total relative volume (% of 1RM × reps) performed. RESULTS: Equivalence testing confidence intervals crossed both g = 0.0 and g = ±0.20 thresholds; suggesting changes in VL50 MT and VL70 MT did not statistically differ between groups but were also inconclusive (VL50: 22.77 ± 4.77 to 21.74 ± 4.17 mm; -3.50% vs. 22.10 ± 4.25 to 20.73 ± 4.49 mm; -6.33%; VL70: 18.47 ± 6.59 to 19.93 ± 7.1 mm; +9.43% vs. 16.91 ± 6.67 to 17.04 ± 5.2 mm; +3.47%). The 7-9 RPE group trained with significantly higher intensity (82.2 ± 5.18 vs. 72.0 ± 4.57% of 1RM, p = 0.002) and performed more relative volume (338.7 ± 21.46 vs. 380.1 ± 25.83 kg, p = 0.007). CONCLUSIONS: Our findings do not conclusively indicate whether vastus lateralis MT changes were statistically similar or statistically different between groups.

BJS Prize 1 Postoperative electrical muscle stimulation attenuates loss of muscle mass and function following major abdominal surgery: A split body randomised control trial

Abstract Aims Significant loss of muscle mass and function occurs after major abdominal surgery. Neuromuscular electrical stimulation (NMES) has been shown to reduce muscle atrophy in some patient groups, but evidence in postoperative patients is limited. This study assesses the efficacy of NMES in attenuating muscle atrophy following major abdominal surgery. Methods Fifteen patients undergoing open colorectal resection were recruited to a split body randomised control trial and their lower limbs randomised to control (CON) or NMES (STIM). The STIM limb underwent 15 minutes of quadriceps NMES twice daily on postoperative day (POD) 1 to 4. Ultrasound measurement of Vastus Lateralis (VL) cross sectional area (CSA) and muscle thickness (MT) was made preoperatively and on POD 5, as was dynamometer measurement of knee extensor strength (KES). All outcomes were analysed using linear mixed model techniques. The study was approved by NHS research ethics committee (ref 20/EM/069). Results NMES significantly reduced the loss of CSA (-2.52% vs -9.16%, p&amp;lt;0.001), MT (-2.76% vs -8.145, p=0.001) and KES (-10.35% vs -19.69%, p=0.03). No adverse events occurred, and patients reported that NMES caused minimal or no discomfort. Conclusions NMES reduces loss of muscle mass and function following major abdominal surgery and may be an important tool in aiding recovery to normal activity levels. This will be especially important in preventing postoperative loss of independence in the increasingly physiologically frail patients undergoing major abdominal surgery. Further studies should establish the efficacy of bilateral whole-leg NMES for improving patient-centred outcomes.

O101 Increased contractile activity through electrical stimulation attenuates postoperative loss of muscle mass and function, even in the presence of inadequate nutrition

Abstract Introduction Significant muscle atrophy occurs after major abdominal surgery. Lack of physical activity and protein intake may play a significant role. This study assesses the efficacy of neuromuscular electrical stimulation (NMES) in attenuating loss of muscle mass and function following open colorectal resection. Methods Fifteen patients were recruited, and their lower limbs randomised to control (CON) or NMES (STIM). Vastus Lateralis (VL) cross sectional area (CSA), muscle thickness (MT) and knee extensor strength (KES) were measured preoperatively and repeated on postoperative day (POD) 5. Dietary intake was recorded, and nutritional intake calculated. Fifteen minutes of NMES was applied to the quadriceps of the STIM leg twice a day on POD 1–4. All outcomes were analysed using linear mixed model approaches. The study was approved by the NHS REC (ref 20/EM/069). Results NMES significantly reduced the loss of CSA (mean difference (MD) 1.18, 95%CI: 0.75–1.61, p&amp;lt;0.001), MT (MD 0.12, 95%CI: 0.04–0.2, p=0.001) and KES (MD 4.48, 95%CI: 0.00–8.97, p=0.03). Total energy and protein intakes over POD1 - 4 were 42.6% (± 19.7) and 21.1% (± 11.4) of the ESPEN recommended daily amount for perioperative patients. No adverse events occurred, and patients reported that NMES caused minimal or no discomfort. Conclusion NMES has been demonstrated to reduce loss of muscle mass and function following major abdominal surgery and may be an important tool in aiding recovery to normal functional state. Further studies should establish the efficacy of bilateral whole-leg NMES for improving patient centred outcomes. Take-home message Loss of muscle mass and function after major abdominal surgery causes significant morbidity. Neuromuscular electrical stimulation reduces this muscle loss and should be investigated further as a potential therapy.