Limb Muscle Volume Research Articles

Athlete Muscular Phenotypes Identified and Compared with High-Dimensional Clustering of Lower Limb Muscle Volume Measurements.

Athletes use their skeletal muscles to demonstrate performance. Muscle force generating capacity is correlated with volume, meaning that variations in sizes of different muscles may be indicative of how athletes meet different demands in their sports. Medical imaging enables in vivo quantification of muscle volumes; however, muscle volume distribution has not been compared across athletes of different sports. The goal of this work was to define "muscular phenotypes" in athletes of different sports and compare these using hierarchical clustering. Muscle volumes normalized by body mass of athletes (football, baseball, basketball, or track) were compared with control participants to quantify size differences using z -scores. z -Scores of 35 muscles described the pattern of volume deviation within each athlete's lower limb, characterizing their muscular phenotype. Data-driven high-dimensional clustering analysis was used to group athletes presenting similar phenotypes. Efficacy of clustering to identify similar phenotypes was demonstrated by grouping athletes' contralateral limbs before other athletes' limbs. Analyses revealed that athletes did not tend to cluster with others competing in the same sport. Basketball players with similar phenotypes grouped by clustering also demonstrated similarities in performance. Clustering also identified muscles with similar volume variation patterns across athletes, and principal component analysis revealed specific muscles that accounted for most of the variance (gluteus maximus, sartorius, semitendinosus, vastus medialis, vastus lateralis, and rectus femoris). Athletes exhibit heterogeneous lower limb muscle volumes that can be characterized and compared as individual muscular phenotypes. Clustering revealed that athletes with the most similar phenotypes do not always play the same sport such that patterns of muscular heterogeneity across a group of athletes reflect factors beyond their specific sports.

The Rheumatoid Arthritis and MUScle (RAMUS) Study: Protocol for an observational single-arm study of skeletal muscle in patients with rheumatoid arthritis receiving tofacitinib.

People with rheumatoid arthritis (RA) are disproportionately affected by sarcopenia, the generalised loss of muscle strength and mass, consequently facing an increased risk of falls, functional decline and death. Currently, there are no approved pharmacological treatments for sarcopenia. RA patients who start tofacitinib (a Janus kinase inhibitor) develop small increases in serum creatinine that are not explained by renal function changes and could reflect sarcopenia improvement. The RAMUS Study is a proof of concept, single-arm observational study in which patients with RA who commence tofacitinib according to routine care will be offered participation according to eligibility criteria. Participants will undergo lower limb quantitative magnetic resonance imaging, whole-body dual energy x-ray absorptiometry, joint examination, muscle function testing and blood tests at three time points: prior to starting tofacitinib and 1 and 6 months afterwards. Muscle biopsy will be performed before and 6 months after starting tofacitinib. The primary outcome will be lower limb muscle volume changes following treatment initiation. The RAMUS Study will investigate whether muscle health improves following tofacitinib treatment for RA. Identifying a potential pharmacological treatment for sarcopenia could have important implications for individuals with RA and for older people in general. ISRCTN registry ID: 13364395.

The effect of muscle atrophy in people with unilateral transtibial amputation for three activities: Gait alone does not tell the whole story

Amputation imposes significant challenges in locomotion to millions of people with limb loss worldwide. The decline in the use of the residual limb results in muscle atrophy that affects musculoskeletal dynamics in daily activities. The aim of this study was to quantify the lower limb muscle volume discrepancy based on magnetic resonance (MR) imaging and to combine this with motion analysis and musculoskeletal modelling to quantify the effects in the dynamics of key activities of daily living. Eight male participants with traumatic unilateral transtibial amputation were recruited who were at least six months after receiving their definitive prostheses. The muscle volume discrepancies were found to be largest at the knee extensors (35 %, p = 0.008), followed by the hip abductors (17 %, p = 0.008). Daily activities (level walking, standing up from a chair and ascending one step) were measured in a motion analysis laboratory and muscle and joint forces quantified using a detailed musculoskeletal model for people with unilateral transtibial amputation which was calibrated in terms of the muscle volume discrepancies post-amputation at a subject-specific level. Knee extensor muscle forces were lower at the residual limb than the intact limb for all activities (p ≤ 0.008); residual limb muscle forces of the hip abductors (p ≤ 0.031) and adductors (p ≤ 0.031) were lower for standing-up and ascending one step. While the reduced knee extensor force has been reported by other studies, our results suggest a new biomechanically-based mitigation strategy to improve functional mobility, which could be achieved through strengthening of the hip abd/adductor muscles.

The relationship between lower limb muscle volume and peak vertical jump power in children

BACKGROUND: Vertical jump is an index representing leg power. It is important to determine factors that influence the vertical jump to help athletes improve their leg power. OBJECTIVE: This study aimed to determine the relationship between lower limbs muscle volume and peak vertical jump (VJ) power in children for both sexes. METHODS: Fourty children healthy boys (n= 20) and girls (n= 20) aged 10 to 12 years old, randomly performed three VJ modalities: squat jump (SJ), counter movement jump without (CMJ) and with arm swings (CMJarms). Lower limbs muscle volume (MV) estimated using a standard anthropometric method. Peak power (PP) calculated by Sayers equation. RESULTS: significant correlations between MV and Peak vertical jump power showed for both sexes. Likewise, significant correlations were found between MV and body mass for boys (r= 0.66; p= 0.001) and for girls (r= 0.59; p= 0.006). CONCLUSIONS: The correlation observed between peak vertical jump power and MV in both sexes can be considered as estimation tool of the lower limbs muscle power. Lower limb’s muscle volume are determining factor in muscle power for both sexes.

Do Liquid Nitrogen-treated Tumor-bearing Nerve Grafts Have the Capacity to Regenerate, and Do They Pose a Risk of Local Recurrence? A Study in Rats.

Under most circumstances, the resection of soft tissue sarcomas of the extremities can be limb-sparing, function-preserving oncologic resections with adequate margins. However, en bloc resection may require resection of the major peripheral nerves, causing poor function in the extremities. Although liquid nitrogen treatment has been used to sterilize malignant bone tumors, its use in the preparation of nerve grafts has, to our knowledge, not been reported. Hence, this study aimed to investigate the tumor recurrence and function after peripheral nerve reconstruction using liquid nitrogen-treated tumor-bearing nerves in a rat model. (1) Do liquid nitrogen-treated frozen autografts have regeneration capabilities? (2) Do liquid nitrogen-treated tumor-bearing nerves cause any local recurrences in vivo in a rat model? Experiment 1: Twelve-week-old female Wistar rats, each weighing 250 g to 300 g, were used. A 10-mm-long section of the right sciatic nerve was excised; the prepared nerve grafts were bridge-grafted through end-to-end suturing. The rats were grouped as follows: an autograft group, which underwent placement of a resected sciatic nerve after it was sutured in the reverse orientation, and a frozen autograft group, which underwent bridging of the nerve gap using a frozen autograft. The autograft was frozen in liquid nitrogen, thawed at room temperature, and then thawed in distilled water before application. The third group was a resection group in which the nerve gap was not reconstructed. Twenty-four rats were included in each group, and six rats per group were evaluated at 4, 12, 24, and 48 weeks postoperatively. To assess nerve regeneration after reconstruction using the frozen nerve graft in the nontumor rat model, we evaluated the sciatic functional index, tibialis anterior muscle wet weight ratio, electrophysiologic parameters (amplitude and latency), muscle fiber size (determined with Masson trichrome staining), lower limb muscle volume, and immunohistochemical findings (though neurofilament staining and S100 protein produced solely and uniformly by Schwann cells associated with axons). Lower limb muscle volume was calculated via CT before surgery (0 weeks) and at 4, 8, 12, 16, 20, 24, 32, 40, and 48 weeks after surgery. Experiment 2: Ten-week-old female nude rats (F344/NJcl-rnu/rnu rats), each weighing 100 g to 150 g, were injected with HT1080 (human fibrosarcoma) cells near the bilateral sciatic nerves. Two weeks after injection, the tumor grew to a 10-mm-diameter mass involving the sciatic nerves. Subsequently, the tumor was resected with the sciatic nerves, and tumor-bearing sciatic nerves were obtained. After liquid nitrogen treatment, the frozen tumor-bearing nerve graft was trimmed to a 5-mm-long tissue and implanted into another F344/NJcl-rnu/rnu rat, in which a 5-mm-long section of the sciatic nerve was resected to create a nerve gap. Experiment 2 was performed with 12 rats; six rats were evaluated at 24 and 48 weeks postoperatively. To assess nerve regeneration and tumor recurrence after nerve reconstruction using frozen tumor-bearing nerve grafts obtained from the nude rat with human fibrosarcoma involving the sciatic nerve, the sciatic nerve's function and histologic findings were evaluated in the same way as in Experiment 1. Experiment 1: The lower limb muscle volume decreased once at 4 weeks in the autograft and frozen autograft groups and gradually increased thereafter. The tibialis anterior muscle wet weight ratio, sciatic functional index, muscle fiber size, and electrophysiologic evaluation showed higher nerve regeneration potential in the autograft and frozen autograft groups than in the resection group. The median S100-positive areas (interquartile range [IQR]) in the autograft group were larger than those in the frozen autograft group at 12 weeks (0.83 [IQR 0.78 to 0.88] versus 0.57 [IQR 0.53 to 0.61], difference of medians 0.26; p = 0.04) and at 48 weeks (0.86 [IQR 0.83 to 0.99] versus 0.74 [IQR 0.69 to 0.81], difference of median 0.12; p = 0.03). Experiment 2: Lower limb muscle volume decreased at 4 weeks and gradually increased thereafter. The median muscle fiber size increased from 0.89 (IQR 0.75 to 0.90) at 24 weeks to 1.20 (IQR 1.08 to 1.34) at 48 weeks (difference of median 0.31; p< 0.01). The median amplitude increased from 0.60 (IQR 0.56 to 0.67) at 24 weeks to 0.81 (IQR 0.76 to 0.90) at 48 weeks (difference of median 0.21; p < 0.01). Despite tumor involvement and freezing treatment, tumor-bearing frozen grafts demonstrated nerve regeneration activity, with no local recurrence observed at 48 weeks postoperatively in nude rats. Tumor-bearing frozen nerve grafts demonstrated nerve regeneration activity, and there was no tumor recurrence in rats in vivo. A frozen nerve autograft has a similar regenerative potential to that of a nerve autograft. Although the findings in a rat model do not guarantee efficacy in humans, if they are substantiated by large-animal models, clinical trials will be needed to evaluate the efficacy of tumor-bearing frozen nerve grafts in humans.

Effects of a combined progressive resistance training and functional electrical stimulation-evoked cycling exercise on lower limb muscle strength of individuals with incomplete spinal cord injury: A randomized controlled study.

This study was conducted to investigate the effects of combined progressive resistance training (PRT) and functional electrical stimulation-evoked leg cycling exercise (FES-LCE) on isometric peak torque and muscle volume in individuals with incomplete spinal cord injury. In the single-blind, randomized controlled trial performed between April 2015 and August 2016, 28 participants were randomized between two exercise interventions (FES-LCE+PRT and FES-LCE alone), and training was conducted over 12 weeks. The isometric muscle peak torque and muscle volume for both lower limbs were measured at the baseline and after 6 and 12 weeks. Linear mixed-model analysis of variance was performed to test the effects of FES-LCE+PRT versus FES-LCE on each outcome measure over time via an intention-to-treat analysis. Twenty-three participants (18 males, 5 females; mean age: 33.4±9.7 years; range 21 to 50 years) completed study (10 in the FES-LCE+PRT group, and 13 in the FES-LCE group). The 12-week pre-and posttraining change for left hamstrings' muscle peak torque in the FES-LCE+PRT group (mean difference=4.5±7.9 Nm, 45% change, p<0.05) was consistently higher than that in the FES-LCE group (mean difference=2.4±10.3 Nm, 4% change; p<0.018). The improvement in the right quadriceps muscle's peak torque of the FES-LCE+PRT group (mean difference=19±7.6 Nm, 31% change, p<0.05) was more significant compared to the FES-LCE group. The left muscle volume showed a remarkable increase after 12 weeks in the FES-LCE+PRT group (mean difference=0.3±9.3 L, 7% change, p<0.05). The combination of PRT and FES-LCE was better in improving lower limb muscle strength and volume in chronic incomplete individuals with spinal cord injury.

Short-Term Muscle Power Is Related to Lower Limb Muscle Volume in Young Children.

Muscle power is a component of muscular fitness and is proportional to its volume. Reduced muscular fitness in children is linked to negative health outcomes. Associations between muscle volume (MV) and power have not been examined in young children and could reveal important insights into early neuromuscular development. Forty-four children (2-8y) completed 3 tests of short-term muscular power: repeated anaerobic sprint test, vertical jump, and horizontal jump. MV was assessed using 3D ultrasound for 3 lower limb muscles (rectus femoris, medial gastrocnemius, and tibialis anterior) and summed for across legs. Associations between muscular power and summed MV were assessed using Pearson correlation (r). Sex-based differences in muscular power and MV were assessed using 1-way analysis of covariance. Moderate-strong associations (r = .57 - .87) were found between muscular power and summed MV. No differences were found between boys and girls for height, weight, MV, or muscular power. Young children who have larger lower limb muscles perform better at tasks dependent on short-term muscular power, such as running and jumping, compared with children with smaller muscles. Sex-based differences in short-term muscular power do not exist in young children and reflect similar anthropometry, including lower limb MV.

Hind foot drumming: Volumetric micro-computed tomography investigation of the hind limb musculature of three African mole-rat species (Bathyergidae).

Several species of African mole-rats use seismic signalling by means of hind foot drumming for communication. The present study aimed to create three-dimensional reconstructions and compare volumetric measurements of 27muscles of the hind limb of two drumming (Georychus capensis and Bathyergus suillus) and one non-drumming (Cryptomys hottentotus natalensis) species of African mole-rats. Diffusible iodine contrast-enhanced micro-computed tomography (diceCT) scans were performed on six specimens per species. Manual segmentation of the scans using VGMAX Studio imaging software allowed for individual muscles to be separated while automatically determining the volume of each muscle. The volume of the individual muscles was expressed as a percentage of the total hind limb volume and statistically compared between species. Subsequently, three-dimensional reconstructions of these muscles were created. Musculus gracilis anticus had a significantly larger percentage of the total hind limb muscle volume in both drumming species compared to the non-drumming C. h. natalensis. Furthermore, several hip and knee extensors, namely mm. gluteus superficialis, semimembranosus, gluteofemoralis, rectus femoris and vastus lateralis, had significantly larger muscle volume percentages in the two drumming species (G. capensis and B. suillus) compared to the non-drumming species. While not statistically significant, G. capensis had larger muscle volume percentages in several key hip and knee extensors compared to B. suillus. Additionally, G capensis had the largest summed percentage of the total hind limb volume in the hip flexor, hip extensor, knee extensor and ankle plantar flexor muscle groups in all the three species. This could be indicative of whole muscle hypertrophy in these muscles due to fast eccentric contractions that occur during hind foot drumming. However, significantly larger muscle volume percentages were observed in the scratch digging B. suillus compared to the other two chisel tooth digging species. Moreover, while not statistically significant, B. suillus had larger muscle volume percentages in several hip extensor and knee flexor muscles compared to G. capensis (except for m. vastus lateralis). These differences could be due to the large relative size of this species but could also be influenced by the scratch digging strategy employed by B. suillus. Therefore, while the action of hind foot drumming seems to influence certain key muscle volumes, digging strategy and body size may also play a role.

Role of Lower Limb Muscle Strength in Knee Osteoarthritis Progression for Patients With Mild and Moderate Knee Osteoarthritis.

We aimed to elucidate the association of lower limb muscle strength with the volume loss of cartilages/menisci for patients with mild and moderate knee osteoarthritis. One hundred seventy individuals with mild and moderate knee osteoarthritis were included from the Osteoarthritis Initiative database. Five muscle strength variables were measured from isometric strength test. The measurement of volume on medial and lateral menisci and seven subregional cartilages from knee magnetic resonance scans were used for assessing 2-yr osteoarthritis progression. Along with the decreased lower limb muscle strength, the volume of patellar cartilage, medial meniscus, and lateral meniscus decreased more than cartilage on tibia and weight-bearing femoral condyle. However, the cartilage volume on the entire medial and lateral femoral condyle increased significantly. The maximum quadricep strength was the most sensitive muscle strength variable, and we found that it was more positively correlated with lateral meniscus volume than with other subregions at baseline and 24-mo follow-up. This study shows the relationship between lower limb muscle strength and volumes of cartilage and meniscus for patients with mild and moderate knee osteoarthritis. In addition, our study indicates a biomechanical mechanism of quadricep strength and meniscus-related knee dynamic stability in progression of mild-to-moderate knee osteoarthritis.

Understanding lower limb muscle volume adaptations to amputation

Amputation of a major limb, and the subsequent return to movement with a prosthesis, requires the development of compensatory strategies to account for the loss. Such strategies, over time, lead to regional muscle atrophy and hypertrophy through chronic under or overuse of muscles compared to uninjured individuals. The aim of this study was to quantify the lower limb muscle parameters of persons with transtibial and transfemoral amputations using high resolution MRI to ascertain muscle volume and to determine regression equations for predicting muscle volume using femur- and tibia-length, pelvic-width, height, and mass. Twelve persons with limb loss participated in this study and their data were compared to six matched control subjects. Subjects with unilateral transtibial amputation showed whole-limb muscle volume loss in the residual-limb, whereas minor volume changes in the intact limb were found, providing evidence for a compensation strategy that is dominated by the intact-limb. Subjects with bilateral-transfemoral amputations showed significant muscle volume increases in the short adductor muscles with an insertion not affected by the amputation, the hip flexors, and the gluteus medius, and significant volume decreases in the longer adductor muscles, rectus femoris, and hamstrings.This study presents a benchmark measure of muscle volume discrepancies in persons with limb-loss, and can be used to understand the compensation strategies of persons with limb-loss and the impact on muscle volume, thus enabling the development of optimised intervention protocols, conditioning therapies, surgical techniques, and prosthetic devices that promote and enhance functional capability within the population of persons with limb loss.

Effects of Elastic Band Plyometric Training on Physical Performance of Team Handball Players

This project investigated the effect of incorporating 8 weeks of biweekly upper limb loaded plyometric training (using elastic bands) into the in-season regimen of handball players. Participants were randomly allocated to a control group (CG) (n = 15, age = 18.1 ± 0.5 years, body mass = 73.7 ± 13.9 kg), or an experimental group (EG) (n = 14, age = 17.7 ± 0.3 years, body mass = 76.8 ± 10.7 kg). The measurements obtained pre- and post-intervention included a cycle ergometer force–velocity test, ball throwing velocity in three types of throwing, one-repetition maximum (1-RM) bench press and pull-over, and anthropometric estimates of the upper limb muscle volumes. The EG improved in absolute muscle power (W) (Δ23.3%; interaction effect p = 0.032 more than pre-intervention), relative muscle power (W·kg−1) (Δ22.3%; interaction effect p = 0.024), and all three types of ball throwing (Δ18.6%, interaction effect p = 0.019 on a jumping shot; Δ18.6%, interaction effect p = 0.017 on a three-step running throw; and Δ19.1%, interaction effect p = 0.046 on a standing throw). There was no interaction effect for the 1-RM bench press and pull-over performance. The upper limb muscle volumes remained unchanged in both groups. We concluded that adding biweekly elastic band plyometric training to standard training improves the muscle power and throwing velocity. Accordingly, such exercises should be adopted as a part of a pragmatic approach to handball training.

In-Season Weightlifting Training Exercise in Healthy Male Handball Players: Effects on Body Composition, Muscle Volume, Maximal Strength, and Ball-Throwing Velocity.

This study assessed the impact of 8 weeks biweekly in-season weightlifting training on the strength, throwing ability, and body composition of healthy male handball players. Twenty players (age: 21.2 ± 0.7 years, height: 1.83 ± 0.08 m, body mass: 83.3 ± 7.5 kg, body fat: 13.2 ± 1.4%, upper limb muscle volume: 3.16 ± 0.16 L) were randomly allocated between experimental (EG) and control (CG) groups. Measures of one-repetition maximal strength included bench press, pull-over, snatch, and clean and jerk. Throwing velocity was investigated by standing, running, and jump throws, and the power of the upper limbs was estimated from the total distance of a 3-kg medicine ball overhead throw. Muscle volumes were estimated anthropometrically. Training sessions comprised 3–4 sets of explosive weightlifting exercise at 75%–90% of 1RM (repetition maximum). Significant interaction effects (time x group) were found for all strength and throwing variables, ranging from ηp2 = 0.595 (pull-over) to ηp2 = 0.887 (medicine ball throw), with the largest between-group difference (more than 40%, Δd = 6.65) and effect size (d = 6.44) for the medicine ball throw, and the smallest (about 23%, Δd = 1.61) for the standing shot performance. Significant interaction effects were also detected for all anthropometric parameters (body mass: ηp2 = 0.433; body fat: ηp2 = 0.391; upper limb muscle volume: ηp2 = 0.920, with an almost 20% gain of muscle volume). It can be concluded that 8 weeks of biweekly in-season weightlifting training yielded substantial increases of muscle volume, maximal strength of the upper limbs, and ball throwing velocity in healthy handball players relative to their standard training program.

Effects of squat training with different depths on lower limb muscle volumes.

The purpose of this study was to compare the effects of squat training with different depths on lower limb muscle volumes. Seventeen males were randomly assigned to a full squat training group (FST, n = 8) or half squat training group (HST, n = 9). They completed 10weeks (2days per week) of squat training. The muscle volumes (by magnetic resonance imaging) of the knee extensor, hamstring, adductor, and gluteus maximus muscles and the one repetition maximum (1RM) of full and half squats were measured before and after training. The relative increase in 1RM of full squat was significantly greater in FST (31.8 ± 14.9%) than in HST (11.3 ± 8.6%) (p = 0.003), whereas there was no difference in the relative increase in 1RM of half squat between FST (24.2 ± 7.1%) and HST (32.0 ± 12.1%) (p = 0.132). The volumes of knee extensor muscles significantly increased by 4.9 ± 2.6% in FST (p < 0.001) and 4.6 ± 3.1% in HST (p = 0.003), whereas that of rectus femoris and hamstring muscles did not change in either group. The volumes of adductor and gluteus maximus muscles significantly increased in FST (6.2 ± 2.6% and 6.7 ± 3.5%) and HST (2.7 ± 3.1% and 2.2 ± 2.6%). In addition, relative increases in adductor (p = 0.026) and gluteus maximus (p = 0.008) muscle volumes were significantly greater in FST than in HST. The results suggest that full squat training is more effective for developing the lower limb muscles excluding the rectus femoris and hamstring muscles.

Changes in Muscle Morphology Following Gastrocnemius Recession for Achilles Tendinopathy: A Prospective Cohort Imaging Study.

Background. The purpose of this study was to evaluate changes in posterior compartment muscle volume and intramuscular fat content following gastrocnemius recession in people with Achilles tendinopathy (AT). Methods. Eight patients diagnosed with unilateral recalcitrant AT and an isolated gastrocnemius contracture participated in this prospective cohort study. Magnetic resonance imaging was performed on both limbs of each participant before and 6 months following an isolated gastrocnemius recession. Involved limb muscle volumes and fat fractions (FFs) of the medial gastrocnemius, lateral gastrocnemius, and soleus muscle were normalized to the uninvolved limb. Preoperative to postoperative comparisons were made with Wilcoxon signed-rank tests. Results. Soleus or lateral gastrocnemius muscle volumes or FFs were not significantly different between study time points. A significant difference was found in medial gastrocnemius muscle volume (decrease; P = .012) and FF (increase; P = .017). Conclusion. A major goal of the Strayer gastrocnemius recession, selective lengthening of the posterior compartment while preserving soleus muscle morphology, was supported. The observed changes isolated to the medial gastrocnemius muscle may reduce ankle plantarflexion torque capacity. Study findings may help inform selection of surgical candidates, refine anticipated outcomes, and better direct postoperative rehabilitation following gastrocnemius recession for AT.Levels of Evidence: Level IV: Prospective cohort study.

Playing Level and Position Differences in Body Characteristics and Physical Fitness Performance Among Male Team Handball Players.

The primary aim of the study was to examine the anthropometric characteristics, as well as the physical performance of professional handball players classified by playing position and competition level. Twenty male players (age: 20.4 ± 0.88 years) from the first handball league and 18 male players (age: 21.3 ± 1.61 years) from the second handball league were categorized as backs (8/8), pivots (5/4), and wings (7/6). The following variables were measured in both groups: peak power; vertical squat jump (SJ), and countermovement jump (CMJ); sprint times over 15 and 30 m; handball throwing velocity during the jump shot (JS); and 3 steps shot (T3 step); upper and lower limb muscle volumes; Yo-Yo Intermittent Recovery Test. Anthropometric data revealed significantly (p = 0.003, = 0.248) less muscle volume for second league players (3.13 ± 0.29 l) than for first league (3.71 ± 0.82 l). The cross-sectional area for the first league players was also larger (p = 0.010, = 0.192). Regarding performance parameters, we found significant (p < 0.05 and > 0.20) league differences in five of 15 (33%) performance parameters: running throw ( = 0.285), SJ power ( = 0.670), SJ velocity ( = 0.900), peak upper limb power ( = 0.231) and Yo-Yo-IR 1 ( = 0.348). The second league players showed higher SJ velocity than the first league players ( = 0.900). In contrast, we detected a greater difference in SJ power ( = 0.670) but in favor of the first league players. Pivots were the players with the highest throwing velocity and wings were the fastest (15, 30 m sprint), strongest (countermovement jump), and most enduring (Yo-Yo-IR 1) athletes. Backs showed consistently the lowest level throwing velocity and sprint performance (exception: second league). The anthropometric differences between playing levels and playing positions may indicate the advantageous characteristics that the respective position demands, whereas the playing position differences in physical fitness characteristics may indicate training specificity issues that must be addressed cautiously.

744-P: Associated Factors with Limb Muscle Volume Distribution in Type 2 Diabetes

Background: Type 2 diabetes (T2DM) and sarcopenia have a reciprocal association and could cause a vicious cycle. Resistance training has been proposed to prevent the cycle. It has been postulated that the associated factors with upper limb muscle volume (MV) and lower limb MV were different in T2DM. For efficient resistance training programs, it is needed to understand the factors affect to the imbalance between upper and lower limb MV in T2DM. Aim: We aimed to clarify the clinical associated factors for lower-to-upper limb MV ratio in T2DM. Method: We assessed in 505 patients with T2DM visited at Osaka City Hospital (male: n=303, mean ages 63.5±13.1, female: n=202, mean ages 64.3±13.4). MV in upper and lower limb were measured by a bioelectrical impedance analysis. The association between lower-to-upper limb MV ratio and clinical parameters were investigated. Results: Mean body mass index (BMI) were 26.2±5.0kg/m2 in male and 26.8±5.5kg/m2 in female. Mean lower-to-upper limb MV ratio were significantly lower in male than female (male: 2.9±0.3 vs. female: 3.2±0.5, p&amp;lt;0.001). Mean lower-to-upper limb MV ratio in male was correlated with age, BMI, visceral fat area (VFA), estimated GFR (eGFR), hemoglobin (Hb), C reactive protein (CRP). In female, that was correlated with age, BMI, VFA, Hb, CRP and HbA1c. Multiple regression analysis showed that BMI and Hb were the negative independent factors, and VFA and systolic blood pressure were the positive independent factors for lower-to-upper limb MV ratio in male T2DM (R2=0.262, p&amp;lt;0.001). In female T2DM, BMI was the negative independent factor for lower-to-upper limb MV ratio. Notably, VFA exhibit positive correlation to lower-to-upper limb MV ratio in male obese T2DM (r=-0.252, p=0.001), but VFA negatively correlated in male non-obese T2DM (r=0.244, p=0.006). Conclusions: Gender, blood pressure, Hb and especially visceral obesity, were the important relevant factors for imbalance between upper and lower limb muscle volume in type 2 diabetes. Disclosure K. Motoyama: None. S. Tazoe: None. A. Tamai: None. T. Sakura: None. M. Ohara: None. Y. Yakushiji: None. M. Fukumoto: None. M. Hosoi: Speaker's Bureau; Self; Eli Lilly and Company.

Measuring muscle size and symmetry in healthy adult males using a time-efficient analysis of magnetic resonance images

Objective: Muscle volume (MV) analysis from magnetic resonance imaging (MRI) is time-intensive, and limited measurement reliability data are available. This study investigated a method to reduce lower limb MV analysis time demands, established reliability of these measurements, and applied the findings to quantify muscle size and symmetry in healthy adult males. Approach: Bilateral MRI images were acquired from 15 healthy males (age: 26.5 ± 4.6 years, height: 1.81 ± 0.09 m, body mass: 80.4 ± 12.4 kg) for the entire lower limb. In two participants, the individual gluteals, quadriceps, hamstrings, and triceps surae were manually outlined every 5 mm and MV calculated using 5, 10, 15, 20, 25, and 30 mm distances between images to determine an appropriate distance for reducing analysis time. For all 15 participants, 35 muscles in each limb were manually outlined every 15 mm for use in MV calculations. Reliability of muscle cross-sectional area (CSA) measurement was determined within- and between-sessions and MV measurement reliability determined between-sessions. Between-limb symmetry was calculated using symmetry indices. Main results: A 15 mm inter-slice distance was appropriate for measuring MV (mean difference compared to reference method: 0.7% ± 0.7%). Between-session measurement reliability was good for MV (Typical Error preferred kicking limb (TEP): 1.2%, non-preferred kicking limb (TENP): 0.8%) and CSA (TEP: 3.4% ± 2.9%, TENP: 3.2% ± 1.9%) although CSA Typical Error was larger with increased between-session time (TEP: 4.1% ± 3.1%, TENP: 4.7% ± 4.0%). Between-limb differences in MV were small (mean symmetry index: 0.4% ± 4.1%). Absolute differences in individual MV were larger (mean: 12.6% ± 2.6%), but representing muscles as functional anatomical groups showed smaller absolute between-limb differences (mean: 4.7% ± 1.8%). Significance: MV analysis time demand can be reduced by increasing the distance between analysed MRI slices, although participant height, muscle length and muscle shape require consideration. Small between-limb muscle size differences have been reported in adult males.

Selective motor control and gross motor function in bilateral spastic cerebral palsy

To investigate the relationship between selective motor control (SMC), muscle volume, and spasticity with gross motor function in adolescents and young adults with bilateral spastic cerebral palsy (CP). Eleven male participants with CP (mean age 15y 7mo, standard deviation 3y 6mo, range 12y 1mo-23y 1mo) in Gross Motor Function Classification System (GMFCS) levels I to IV took part in this cross-sectional study. Magnetic resonance imaging (MRI) of both lower limbs of all participants were acquired, from which 18 muscles were manually segmented and muscle volume calculated by a single assessor. Muscle volumes were normalized to body mass and averaged between limbs for each individual. SMC was assessed using Selective Control Assessment of the Lower Extremity (SCALE). Spasticity was assessed using the Modified Ashworth Scale (MAS), and gross motor functional ability was assessed using the Gross Motor Function Measure (GMFM-66). GMFM-66 was strongly positively correlated to SCALE (r=0.901, p≤0.001) and lower limb muscle volume normalized to body mass (r=0.750, p=0.008). MAS was significantly correlated with GMFM-66 (r=-0.691, p=0.018). SMC is a major factor influencing gross motor function in individuals with CP. Lower limb muscle volume and spasticity also influence gross motor function. Selective motor control is a major factor of gross motor function in adolescents and young adults with bilateral cerebral palsy (CP). Gross motor function is related to muscle size and level of spasticity in adolescents and young adults with bilateral CP.

Individuals with mild-to-moderate hip osteoarthritis have lower limb muscle strength and volume deficits

BackgroundIndividuals with advanced hip osteoarthritis (OA) exhibit generalized muscle weakness of the affected limb and so clinical practice guidelines recommend strength training for the management of hip OA. However, the extent and pattern of muscle weakness, including any between-limb asymmetries, in early stages of the disease are unclear. This study compared hip and knee muscle strength and volumes between individuals with mild-to-moderate symptomatic and radiographic hip OA and a healthy control group.MethodsNineteen individuals with mild-to-moderate symptomatic and radiographic hip OA (n = 12 unilateral; n = 7 bilateral) and 23 age-matched, healthy controls without radiographic hip OA or hip pain participated. Isometric strength of the hip and knee flexors and extensors, and hip abductors and adductors were measured. Hip and thigh muscle volumes were measured from lower limb magnetic resonance images. A full-factorial, two-way General Linear Model was used to assess differences between groups and between limbs.ResultsParticipants in the hip OA group demonstrated significantly lower knee flexor, knee extensor, hip flexor, hip extensor and hip abductor strength compared to controls and had significantly lower volume of the adductor, hamstring and quadriceps groups, and gluteus maximus and gluteus minimus muscles, but not tensor fasciae latae or gluteus medius muscles. There were no between-limb strength differences or volume differences within either group.ConclusionsAtrophic, bilateral hip and knee muscle weakness is a feature of individuals with mild-to-moderate hip OA. Early interventions to target muscle weakness and prevent the development of strength asymmetries that are characteristic of advanced hip OA appear warranted.

P 110 – Lower limb muscle volume estimation from maximum cross-sectional area and muscle length in cerebral palsy and typically developing individuals

BackgroundDeficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy. MethodsLower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy(14.7 ± 3 years, 17 male) and 23 typically developing individuals (16.8 ± 3.3 years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb. FindingsAnalysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%. InterpretationThis study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic.