Validity of ultrasonograph muscle thickness measurements for estimating muscle volume of knee extensors in humans

Cross-sectional area measurements versus volumetric assessment of the quadriceps femoris muscle in patients with anterior cruciate ligament reconstructions

OBJECTIVE

Our aim was to validate the use of cross-sectional area (CSA) measurements at multiple quadriceps muscle levels for estimating the total muscle volume (TMV), and to define the best correlating measurement level.

METHODS

Prospective institutional review board (IRB)-approved study with written informed patient consent. Thighs of thirty-four consecutive patients with ACL-reconstructions (men, 22; women, 12) were imaged at 1.5-T using three-dimensional (3D) spoiled dual gradient-echo sequences. CSA was measured at three levels: 15, 20, and 25 cm above the knee joint line. TMV was determined using dedicated volumetry software with semiautomatic segmentation. Pearson's correlation and regression analysis (including standard error of the estimate, SEE) was used to compare CSA and TMV.

RESULTS

The mean ± standard deviation (SD) for the CSA was 60.6 ± 12.8 cm(2) (range, 35.6-93.4 cm(2)), 71.1 ± 15.1 cm(2) (range, 42.5-108.9 cm(2)) and 74.2 ± 17.1 cm(2) (range, 40.9-115.9 cm(2)) for CSA-15, CSA-20 and CSA-25, respectively. The mean ± SD quadriceps' TMV was 1949 ± 533.7 cm(3) (range, 964.0-3283.0 cm(3)). Pearson correlation coefficient was r = 0.835 (p < 0.01), r = 0.906 (p < 0.01), and r = 0.956 (p < 0.01) for CSA-15, CSA-20 and CSA-25, respectively. Corresponding SEE, expressed as percentage of the TMV, were 15.2%, 11.6% and 8.1%, respectively.

CONCLUSION

The best correlation coefficient between quadriceps CSA and TMV was found for CSA-25, but its clinical application to estimate the TMV is limited by a relatively large SEE.

KEY POINTS

• Cross-sectional area was used to estimate QFM size in patients with ACL-reconstruction • A high correlation coefficient exists between quadriceps CSA and volume • Best correlation was seen 25 cm above the knee joint line • A relatively large standard error of the estimate limits CSA application.

Estimation of gastrocnemius muscle volume using ultrasonography in children with spastic cerebral palsy

PURPOSE

This study aimed to investigate useful parameters for estimating gastrocnemius (GCM) muscle volume (MV) using ultrasonography (US) and anthropometry in children with spastic cerebral palsy (CP).

MATERIALS AND METHODS

Eighteen legs from nine children with spastic CP aged 2 to 6 years were investigated in this study. Tibial length (TL) of each leg was measured and muscle thickness (MT) and anatomical cross-sectional area (aCSA) of GCM muscles were assessed using US. The volume of the GCM was measured by magnetic resonance imaging (MRI) scans. The relationship of TL, MT, and aCSA with MV measured by MRI was investigated. Simple and multiple regression analyses were performed to establish muscle volume prediction equations.

RESULTS

Resting MT, aCSA, and TL were highly related to MV of both medial and lateral head of GCM determined by MRI. The MV prediction equation based on simple regression analysis resulted in r² values ranging from 0.591 to 0.832 (p<0.05). The r² values were higher using aCSA as independent variable than using MT. The MV prediction equation based on multiple regression analysis resulted in r² values ranging from 0.779 to 0.903 (p<0.05). However, the relatively high standard error of the estimate values ranged from 18.0-33.6% on simple regression and 15.5-25.6% on multiple regression. The contribution of aCSA was higher than that of MT for predicting MV of GCM.

CONCLUSION

Our study demonstrated the suitability of US assessment of aCSA and MT combined with TL for estimating MV of GCM in children with spastic CP and showed that aCSA is more useful parameter than MT.

Site-specific thigh muscle loss as an independent phenomenon for age-related muscle loss in middle-aged and older men and women

The purpose of this study was to examine the relationships between dual-energy X-ray absorptiometry (DXA)-determined appendicular lean mass (aLM) and ultrasound-measured thigh muscle thickness (MTH) ratio and between aLM or thigh MTH ratio and zigzag walking performance. Eighty-one middle-aged and older adults (41 men and 40 women) aged 50 to 74 years volunteered for the study. Approximately two thirds of the subjects (34 men and 17 women) carried out regular sports activity (at least >2 times a week) including running and cycling exercise. MTH was measured using B-mode ultrasound at two sites on the anterior (A50) and posterior (P50) aspects of the mid-thigh. A50:P50 MTH ratio was calculated to evaluate site-specific thigh muscle loss. aLM and percent body fat were also determined using a DXA. Men had lower body fat and higher aLM than women. Anterior and posterior thigh MTH as well as A50:P50 MTH ratio was higher in men than in women. Zigzag walking time was faster in men than in women. Anterior and posterior thigh MTH was positively (p < 0.001) correlated to aLM and aLM index in men and women. However, A50:P50 MTH ratio was not significantly correlated with aLM and aLM index in both sexes. There was no significant correlation between aLM index and zigzag walking time in men and women. A50:P50 MTH ratio was inversely (p < 0.05) correlated to zigzag walking time in both men and women. Our results suggest that thigh MTH ratio is independent of age-related muscle mass loss detected by aLM.

Strength and endurance training prescription in healthy and frail elderly

Aging is associated with declines in the neuromuscular and cardiovascular systems, resulting in an impaired capacity to perform daily activities. Frailty is an age-associated biological syndrome characterized by decreases in the biological functional reserve and resistance to stressors due to changes in several physiological systems, which puts older individuals at special risk of disability. To counteract the neuromuscular and cardiovascular declines associated with aging, as well as to prevent and treat the frailty syndrome, the strength and endurance training seems to be an effective strategy to improve muscle hypertrophy, strength and power output, as well as endurance performance. The first purpose of this review was discuss the neuromuscular adaptations to strength training, as well as the cardiovascular adaptations to endurance training in healthy and frail elderly subjects. In addition, the second purpose of this study was investigate the concurrent training adaptations in the elderly. Based on the results found, the combination of strength and endurance training (i.e., concurrent training) performed at moderate volume and moderate to high intensity in elderly populations is the most effective way to improve both neuromuscular and cardiorespiratory functions. Moreover, exercise interventions that include muscle power training should be prescribed to frail elderly in order to improve the overall physical status of this population and prevent disability.

Time course of low- and high-volume strength training on neuromuscular adaptations and muscle quality in older women

This study investigated the effects of low- and high-volume strength trainings on neuromuscular adaptations of lower- and upper-body muscles in older women after 6 weeks (6WE), 13 weeks (13WE), and 20 weeks (20WE) of training. Healthy older women were assigned to low-volume (LV) or high-volume (HV) training groups. The LV group performed one set of each exercise, while the HV group performed three sets, 2 days/week. Knee extension and elbow flexion one-repetition maximum (1-RM), maximal isometric strength, maximal muscle activation, and muscle thickness (MT) of the lower- and upper-body muscles, as well as lower-body muscle quality (MQ) obtained by ultrasonography, were evaluated. Knee extension and elbow flexion 1-RM improved at all time points for both groups; however, knee extension 1-RM gains were greater for the HV group after 20WE. Maximal isometric strength of the lower body for both groups increased only at 20WE, while upper-body maximal isometric strength increased after 13WE and 20WE. Maximal activation of the lower and upper body for both groups increased only after 20WE. Both groups showed significant increases in MT of their lower and upper body, with greater gains in lower-body MT for the HV group at 20WE. MQ improved in both groups after 13WE and 20WE, whereas the HV group improved more than the LV group at 20WE. These results showed that low- and high-volume trainings have a similar adaptation time course in the muscular function of upper-body muscles. However, high-volume training appears to be more efficient for lower-body muscles after 20 weeks of training.

Applicability of ultrasound muscle thickness measurements for predicting fat-free mass in elderly population

OBJECTIVE

This study aimed to examine the applicability of ultrasound muscle thickness (MT) measurements for predicting whole body fat-free mass (FFM) in elderly individuals.

DESIGN AND SETTING

Cross-sectional study of 77 healthy elderly individuals.

METHODS

MTs at nine sites of the body and FFM were determined using B-mode ultrasound and dual-energy x-ray absorptiometry (DXA), respectively, in 44 women and 33 men aged 52 to 78 yrs. Stepwise multiple regression analysis produced two equations for predicting DXA-based FFM with sex (dummy: woman = 0 and man = 1) and either MTs at the anterior and posterior of thigh and lower leg (Eq1) or the product of MT and limb length (MT×LL) at thigh anterior and posterior, lower leg posterior, and upper arm anterior (Eq2) as independent variables.

RESULTS

The R2 and SEE for each of the two equations were 0.929 and 2.5 kg for Eq1 and 0.955 and 2.0 kg for Eq2. The estimated FFM from each of Eq1 (44.4 ± 8.9 kg) and Eq2 (44.4 ± 9.0 kg) did not significantly differ from that of the DXA-based FFM (44.4 ± 9.2 kg), without systematic error. However, the absolute value of the difference between the DXA-based and estimated FFM was significantly greater with Eq1 (2.0 ± 1.5 kg) than with Eq2 (1.5 ± 1.3 kg).

CONCLUSION

The current results indicate that ultrasound MT measurement is useful to predict FFM in the elderly, and its accuracy is improved by using the product of MT and limb length as an independent variable.

Association between ultrasound measurements of muscle thickness, pennation angle, echogenicity and skeletal muscle strength in the elderly

The increase of elderly in our society requires simple tools for quantification of sarcopenia in inpatient and outpatient settings. The aim of this study was to compare parameters determined with musculoskeletal ultrasound (M-US) with muscle strength in young and elderly patients. In this prospective, randomised and observer blind study, 26 young (24.2 ± 3.7 years) and 26 old (age 67.8 ± 4.8 years) patients were included. Muscle thickness, pennation angle and echogenicity of all muscles of musculus quadriceps were measured by M-US and correlated with isometric maximum voluntary contraction force (MVC) of musculus quadriceps. Reproducibility of M-US measurements as well as simple and multiple regression models were calculated. Of all measured M-US variables the highest reproducibility was found for measurements of thickness (intraclass correlation coefficients, 85-97%). Simple regression analysis showed a highly significant correlation of thickness measurements of all muscles of musculus quadriceps with MVC in the elderly and in the young. Multiple regression analysis revealed that thickness of musculus vastus medialis had the best correlation with MVC in the elderly. This study showed that measurement of muscle thickness, especially of musculus vastus medialis, by M-US is a reliable, bedside method for monitoring the extent of sarcopenia.

Does quadriceps atrophy exist in individuals with patellofemoral pain? A systematic literature review with meta-analysis

STUDY DESIGN

Systematic literature review.

OBJECTIVES

To investigate whether quadriceps atrophy is present in the affected limb of individuals with patellofemoral pain (PFP).

BACKGROUND

PFP is a common condition. Atrophy of the quadriceps femoris, in particular the vastus medialis obliquus, is often assumed to be present by clinicians, and its resolution may underpin the reported effectiveness of quadriceps strengthening intervention in PFP rehabilitation.

METHODS

A systematic search of the literature was conducted to identify studies that measured the size of the quadriceps in individuals with PFP. Meta-analyses were performed to determine whether quadriceps size in limbs with PFP differed from that in comparison limbs. Separate meta-analyses were performed for quadriceps size measured as girth and quadriceps size measured with imaging (thickness, cross-sectional area, and volume).

RESULTS

Ten studies were included in this review. The meta-analysis of girth measurements (3 studies) found no atrophy in limbs with PFP (P = .638). The meta-analyses for imaging techniques (thickness, cross-sectional area, or volume measurements) showed atrophy in the limb with PFP compared to both the asymptomatic limb (3 studies) (P = .036) and limbs from a comparison group (3 studies) (P = .001). The single study that compared the vastus medialis obliquus and vastus lateralis in individuals with PFP found atrophy of both the vastus medialis obliquus and vastus lateralis but no significant difference in the amount of atrophy between them (P = .179).

CONCLUSION

Quadriceps muscle atrophy was shown to be present in PFP when analyzed by imaging, but not by girth measures. Insufficient data were available to determine if there was greater atrophy of the vastus medialis obliquus than the vastus lateralis. These findings support the rationale for use of quadriceps strengthening as part of a rehabilitation program for PFP.

Validity of ultrasound muscle thickness measurements for predicting leg skeletal muscle mass in healthy Japanese middle-aged and older individuals

Background

The skeletal muscle mass of the lower limb plays a role in its mobility during daily life. From the perspective of physical resources, leg muscle mass dominantly decreases after the end of the fifth decade. Therefore, an accurate estimate of the muscle mass is important for the middle-aged and older population. The present study aimed to clarify the validity of ultrasound muscle thickness (MT) measurements for predicting leg skeletal muscle mass (SM) in the healthy Japanese middle-aged and older population.

Findings

MTs at four sites of the lower limb and the bone-free lean tissue mass (LTM) of the right leg were determined using brightness-mode ultrasonography and dual-energy X-ray absorptiometry (DXA), respectively, in 44 women and 33 men, 52- to 78-years old. LTM was used as a representative variable of leg skeletal muscle mass. In the model-development group (30 women and 22 men), regression analysis produced an equation with R² and standard error of the estimate (SEE) of 0.958 and 0.3 kg, respectively: LTM (kg) = 0.01464 × (MT_SUM×L) (cm²) - 2.767, where MT_SUM is the sum of the product of MTs at four sites, and L is length of segment where MT is determined. The estimated LTM (7.0 ± 1.7 kg) did not significantly differ from the measured LTM (7.0 ± 1.7 kg), without a significant systematic error on a Bland-Altman plot. The application of this equation for the cross-validation group (14 women and 11 men) did not yield a significant difference between the measured (7.2 ± 1.6 kg) or estimated (7.2 ± 1.6 kg) LTM and systematic error.

Conclusion

The developed prediction equation may be useful for estimating the lean tissue mass of the lower extremity for the healthy Japanese middle-aged and older population.

Prediction of the muscle strength by the muscle thickness and hardness using ultrasound muscle hardness meter

PURPOSES

The present study investigated whether a combination of the thickness and hardness of muscles without muscle tension can be used to estimate muscle strength during knee extension in adult males and females.

METHODS

Seventy-two males and thirty-three females, whose ages ranged from 18 to 35 years, participated in this study. We measured muscle thickness and hardness in the right anterior region of the thigh (rectus femoris muscle and vastus intermedius muscle) without muscle tension using an ultrasound muscle hardness meter, and the maximal voluntary isometric contraction of right knee extension (MVIC). The changing ratios (%) of the tissue thickness before compression to those during compression (compression ratio) are calculated as an index of the hardness. Higher ratio indicates a harder muscle compared with that of other individuals showing the same muscle thickness.

RESULTS

In male group, although the MVIC had significantly positive correlation to both muscle thickness (r=0.412, p<0.01) and compression ratio (r=0.233, p<0.05), their variables also had correlation mutually. In the female group, the MVIC has significantly positive correlation to only compression ratio (r=0.499, p<0.01), not muscle thickness (r=0.225, n.s.). On multiple linear regression analysis, the combination of two parameters (muscle thickness and compression ratio) allowed more accurate estimation of MVIC (r=0.573, p<0.01) in the female group.

CONCLUSION

These findings suggested that the combination of muscle thickness and hardness is capable of effectively estimating muscle strength especially in females.

Efficiency of twice weekly concurrent training in trained elderly men

This study compared the effects of different weekly training frequencies on the cardiovascular and neuromuscular adaptations induced by concurrent training in previously trained elderly. After 20weeks of combined strength and endurance training, twenty-four healthy elderly men (65±4 years) were randomly placed into two frequency training groups: strength and endurance training performed twice a week (SE2, n=12); or, strength and endurance training performed three times per week (SE3, n=12). The interventions lasted 10 weeks and each group performed identical exercise intensity and volume per session. Before and after the exercise training, one maximum repetition test (1RM), isometric peak torque (PT), maximal surface electromyographic activity (EMG), as well as muscle thickness (MT) were examined. Additionally, peak oxygen uptake (VO(2peak)), maximum aerobic workload (W(max)), first and second ventilatory thresholds (VT1 and VT2) were evaluated. There were significant increases in upper and lower-body 1RM, MT, VO(2peak), VT1 and VT2, with no differences between groups. There were no changes after training in maximal EMG and isometric peak torque. W(max) was improved only in SE3. After 10 weeks of training, twice weekly combined strength and endurance training leads to similar neuromuscular and cardiovascular adaptations as three times per week, demonstrating the efficiency of lower frequency of concurrent training in previously trained elderly men.

Confiabilidade das medidas de arquitetura do músculo Vasto Lateral pela ultrassonografia

As medidas de confiabilidade das análises da arquitetura muscular pela ultrasonografia são importantes referências para estudos aplicados de mecânica muscular. O objetivo deste estudo foi determinar a confiabilidade das medidas de espessura muscular (EM), ângulo de penação (AP) e comprimento da fibra (CF) do músculo Vasto Lateral (VL). As imagens de ultrassom foram obtidas em um grupo (N=14; 22 ± 1,75 anos) em duas visitas (sessenta medidas por indivíduo). Foi calculado o coeficiente de correlação intraclasse (CCI), coeficiente de variação (CV) e erro típico da medida (ETM). Os resultados demonstram alta confiabilidade: CCI AP (0,83 a 0,99), EM (0,96 a 0,99) e CF (0,80 a 0,99); CV AP (3,68 a 6,34%), EM (3,12 a 3,84%) e CF (3,98 a 6,33%) e ETM AP (0,18 a 0,59º); EM (0,014 a 0,15mm) e CF (0,07 a 1,47mm). Essas medidas devem ser consideradas em estudos que analisam o impacto na arquitetura muscular em programas de condicionamento do Vasto Lateral.

Relationship between site-specific loss of thigh muscle and gait performance in women: the HIREGASAKI study

Sarcopenia is observed as a site-specific loss of skeletal muscle mass, however, it is unknown whether the site-specific sarcopenia is associated with development of physical disability. The purpose of this study was to examine the relationship between age-related thigh muscle loss and gait performance. Fifty-three women aged 52-83 years had their thigh muscle thickness (MTH) measured by ultrasound at five sites on the anterior (30%, 50%, and 70% of thigh length) and posterior (50% and 70% of thigh length) aspects of their thigh. Maximum and normal walking speeds, zig-zag walking time, and maximal voluntary isometric knee extension and flexion strength were measured. Age was inversely correlated to the anterior and posterior MTH ratio (e.g., anterior 50%:posterior 70% MTH ratio [r=-0.426, p=0.002]), thus the site-specific muscle loss of the thigh was observed in the present sample. There were no significant correlations between the anterior/posterior MTH ratio and maximum and normal walking speeds. However, the ratios of anterior 50%:posterior 70% MTH (r=-0.430) and anterior 30%:posterior 70% MTH (r=-0.444) were correlated (p=0.001) to zig-zag walking test. After adjusting for age, height and weight, the anterior 30%:posterior 70% MTH (r=-0.292, p=0.040) was inversely correlated to zig-zag walking performance. Isometric knee extension strength was also inversely correlated to zig-zag walking. Our results suggest that an age-related loss of adductor/quadriceps muscles may be associated with a decrease in a relatively difficult task performance such as zig-zag walking.

A comparison of 2 techniques for measuring rectus femoris muscle thickness in cerebral palsy

PURPOSE

: Precise measures of muscle size are useful when investigating weakness in children with cerebral palsy (CP). Therefore, the purpose of the study was to determine agreement between 2 muscle thickness measurements of the rectus femoris (RF) in CP.

METHODS

: Measures of RF thickness in 13 youth with CP who were ambulatory (mean age: 14.4 ± 3.6 years) were obtained bilaterally using ultrasound imaging. Three measures were obtained at 50% thigh length and averaged (MT50). Maximum muscle thickness (MaxMT) was also determined through repeated measurements toward the proximal insertion of the RF.

RESULTS

: The Bland-Altman plot showed that all values, except for one outlier, fell within 95% limits of agreement (-0.11 to 0.28 cm), showing excellent agreement. However, a constant bias toward higher values with MaxMT method was observed.

CONCLUSION

: Given the time-consuming nature of obtaining MaxMT, the MT50 measurement may be a more feasible alternative when estimating maximum muscle thickness of the RF.

Effect of different frequencies of creatine supplementation on muscle size and strength in young adults

The purpose was to determine if creatine supplementation, consumed immediately before and immediately after exercise, with different dosing frequency (i.e., 2 or 3 d wk) could enhance the gains in muscle size and strength from resistance training (RT) in young adults. A group of 38 physically active, nonresistance trained university students (21-28 years) was randomly allocated to 1 of 4 groups: CR2 (0.15 g·kg creatine during 2 d wk of RT; 3 sets of 10 repetitions; n = 11, 6 men, 5 women), CR3 (0.10 g·kg creatine during 3 d wk of RT; 2 sets of 10 repetitions; n = 11, 6 men, 5 women;), PLA2 (placebo during 2 d wk of RT; n = 8, 5 men, 3 women), and PLA3 (placebo during 3 d wk of RT; n = 8, 4 men, 4 women) for 6 weeks. Before and after training, measurements were taken for muscle thickness of the elbow and knee flexor and extensor muscle groups (ultrasound), 1-repetition maximumleg press and chest press strength, and kidney function (urinary microalbumin). Repeated-measures analysis of variance showed that strength and muscle thickness increased in all groups with training (p < 0.05). The CR2 (0.6 ± 0.9 cm or 20%; p < 0.05) and CR3 groups (0.4 ± 0.6 cm or 16.4%; p < 0.05) experienced greater change in muscle thickness of the elbow flexors compared to the PLA2 (0.05 ± 0.5 cm or 2.3%) and PLA3 groups (0.13 ± 0.7 cm or 6.3%). Men supplementing with creatine experienced a greater increase in leg press strength (77.3 ± 51.2 kg or 62%) compared to women on creatine (21.3 ± 10 kg or 34%, p < 0.05). We conclude that creatine supplementation during RT has a small beneficial effect on regional muscle thickness in young adults but that giving the creatine over 3 d wk did not differ from giving the same dose over 2 d wk.

Muscle architecture predicts maximum strength and is related to activity levels in cerebral palsy

BACKGROUND

Muscle architecture is known to be predictive of muscle function. However, it is unknown whether this relationship is similar in children and adolescents with and without cerebral palsy (CP).

OBJECTIVE

The objective of this study was to determine whether the architecture of the rectus femoris (RF) and vastus lateralis (VL) muscles was predictive of maximum voluntary knee extensor torque in children and adolescents with and without CP and whether these measures were related to activity and participation levels.

DESIGN

A case-control design was used.

METHODS

Eighteen participants with CP (mean age=12.0 years, SD=3.2) at Gross Motor Function Classification System (GMFCS) levels I through IV and 12 age-matched peers with typical development (mean age=12.3 years, SD=3.9) were evaluated. Muscle thickness, fascicle length, and fascicle angle of the RF and VL muscles were measured with 2-dimensional, B-mode ultrasound imaging. The activity and participation measures used for participants with CP were the Pediatric

OUTCOMES

Data Collection Instrument (PODCI) and the Activities Scale for Kids, Performance Version (ASKp).

RESULTS

When age and GMFCS level were controlled for, VL muscle thickness was the best predictor of knee extensor isometric torque in the group with CP (R(2)=.85). This prediction was similar to the prediction from VL muscle thickness and age in participants with typical development (R(2)=.91). Rectus femoris muscle fascicle length was significantly correlated with the Sports and Physical Functioning Scale of the PODCI (ρ=.49), and VL muscle fascicle angle was correlated with the Transfers and Basic Mobility Scale of the PODCI (r=.47) and with ASKp Locomotion subdomain (r=.50).

LIMITATIONS

A limitation of this study was the small sample size.

CONCLUSIONS

Ultrasound measures of VL muscle thickness, adjusted for age and GMFCS level, were highly predictive of maximum torque and have the potential to serve as surrogate measures of voluntary strength (force-generating capacity) in children and adolescents with and without CP.

Age-related changes in elastic properties and moisture content of lower labial mucosa

The purpose of this study was to clarify age-related changes in the elastic properties and moisture content of the lower labial mucosa. Elastic properties and moisture content were also compared between the lower labial mucosa and skin. A total of 85 adults aged 20-82 took part in the study. Elastic properties (distensibility and elasticity) and moisture content of lower labial mucosa and skin were determined in each participant. Measurements for the oral mucosa were taken at the midline of the lower labial mucosa; for the skin, they were taken at the midpoint of the right anterior surface of the forearm. Pearson's correlation coefficient and the Mann-Whitney U test were used for the statistical analysis. A stepwise multiple linear regression analysis was also performed, with age as the dependent variable and sex, distensibility, elasticity and moisture content of the lower labial mucosa as independent variables. A negative correlation was found between age and distensibility of the lower labial mucosa. No correlation was observed between age and elasticity of the lower labial mucosa. A negative correlation was observed between age and moisture content of the lower labial mucosa. A significant difference was observed in moisture content between the 20- to 39-year-old group and the over 40-year-old group. Stepwise analysis identified distensibility and moisture content of the lower labial mucosa as predictive factors of age. The results indicate that distensibility and moisture content of the lower labial mucosa decrease with age. Moisture content in the over 40-year-old group, in particular, was lower than in the 20- to -30-year-old group.

Two modes of weight training programs and patellar stabilization

CONTEXT

Underconditioned patellar stabilizing muscles could be a predisposing factor for patellar instability.

OBJECTIVE

To examine the effect of 2 modes of weight training on the size of the vastus medialis obliquus (VMO), the resting position and passive mobility of the patella, and the strength of the knee extensor muscles.

DESIGN

Prospective intervention, repeated measures in 3 groups.

SETTING

Orthopaedic and sports sciences research laboratory.

PATIENTS OR OTHER PARTICIPANTS

48 healthy adults free from back and lower extremity injuries.

INTERVENTION(S)

Participants were randomly assigned to muscle hypertrophy training, muscle strength training, or the control group. Those in the training groups pursued training 3 times per week for 8 weeks.

MAIN OUTCOME MEASURE(S)

Magnetic resonance imaging and ultrasound cross-sectional area of the VMO, patellar tilt angle on magnetic resonance imaging, instrumented passive patellar mobility, and isometric knee extension torque of the dominant leg.

RESULTS

Participants in both training groups had comparable gains in VMO size, passive patellar stability, and knee extension force, all of which were greater than for the control group (P < .05).

CONCLUSIONS

Both short-term muscle hypertrophy and strength training programs can reinforce the patellar stabilizers in previously untrained volunteers.

Confiabilidade da medida de espessuras musculares pela ultrassonografia

OBJETIVO: Determinar a confiabilidade das medidas de espessuras dos músculos flexores e extensores do cotovelo e joelho pela ultrassonografia (US), quantificando o erro típico associado a essas medidas (ETM). MÉTODOS: A confiabilidade (duas medidas interdias) foi determinada em 15 voluntários aparentemente saudáveis (oito mulheres, 33,9 ± 11,4 anos, 76 ± 21kg, 170 ± 10cm). As imagens da musculatura flexora (FC) e extensora do cotovelo (EC) e flexora (FJ) e extensora do joelho (EJ) foram obtidas pela US bidimensional no modo B, utilizando transdutor de 7,5MHz. As espessuras do tecido muscular compreendidas entre as interfaces com o osso e com o tecido adiposo foram medidas em sítios anatômicos identificados e registrados para ser repetidos na segunda medida. RESULTADOS: A ANOVA não identificou diferenças significativas entre as medidas repetidas. Os coeficientes de correlação intraclasse foram FC = 0,970, EC = 0,971, FJ = 0,555 e EJ = 0,929 (P < 0,05 para todos). Os coeficientes de variação foram de 3,9%, 6,1%, 6,6 % e 4,6%, e os ETM 1,3mm, 1,6mm, 4,9mm e 1,9mm, respectivamente, para espessuras de FC, EC, FJ e EJ. A análise dos gráficos de Bland-Altman apontou que as variáveis não apresentaram erro heterocedástico. CONCLUSÃO: As medidas de espessuras musculares de FC, EC e EJ apresentaram alta confiabilidade, possibilitando seu uso para intervenções como programas de dieta, treinamento físico ou reabilitação. No entanto, o uso da medida de FJ não deve ser recomendada, pois mostrou baixa confiabilidade e alto ETM.

Changes in muscle thickness of gastrocnemius and soleus associated with age and sex

BACKGROUND AND AIMS

Gastrocnemius and soleus in the triceps surae have functional and histological differences.We therefore investigated age-related changes in muscle thickness of these two muscles, as well as the difference in these changes between men and women.

METHODS

Participants comprised 847 healthy adults aged 20 to 79 years. A B-mode ultrasound scanner, with participants sitting on a chair, was used to measure muscle thickness from the midpoint of the gastrocnemius medialis muscle at the level of maximum girth (target point). The ratio of muscle thickness to height was calculated. The inter-rater and intra-rater reliability of measuring muscle thickness with the ultrasound scanner and the validity of the target point were demonstrated before the examination.

RESULTS

Gastrocnemius was significantly thinner in women aged 60 or older and in men aged 50 or older, compared with their counterparts in their 20s. For soleus, no significant differences in thickness were found among the age groups in either sex. Decline in muscle thickness from age 40-79 was greater for gastrocnemius than for soleus.

CONCLUSIONS

These results confirm that gastrocnemius starts to deteriorate earlier and atrophies at a faster pace than soleus. A significant sex difference was found only in the onset age of gastrocnemius deterioration, which was earlier in men than in women.

Abdominal muscle size and symmetry at rest and during abdominal hollowing exercises in healthy control subjects

The symmetry of, and physical characteristics influencing, the thickness of the lateral abdominal muscles at rest and during abdominal exercises were examined in 57 healthy subjects (20 men, 37 women; aged 22-62 years). M-mode ultrasound images were recorded from the abdominal muscles at rest and during abdominal hollowing exercises in hook-lying. The fascial lines bordering the transvs. abdominis, obliquus internus and obliquus externus were digitized and the absolute thickness, relative thickness (% of total lateral thickness) and contraction ratio (thickness during hollowing/thickness at rest), as well as the asymmetry (difference between sides expressed as a percent of the smallest value for the two sides) for each of these parameters were determined for each muscle. Both at rest and during hollowing, obliquus internus was the thickest and transvs. abdominis the thinnest muscle. There were no significant differences between left and right sides for group mean thicknesses of any muscle; however, individual asymmetries were evident, with mean values for the different muscles ranging from 11% to 26%; asymmetry was much less for the contraction ratios (mean % side differences, 5-14% depending on muscle). Body mass was the most significant positive predictor of absolute muscle thickness, for all muscles at rest and during hollowing, accounting for 30-44% variance. Body mass index explained 20-30% variance in transvs. abdominis contraction ratio (negative relationship). The influence of these confounders must be considered in comparative studies of healthy controls and back pain patients, unless groups are very carefully matched. Asymmetries observed in patients should be interpreted with caution, as they are also common in healthy subjects.

Development of an equation to predict muscle volume of elbow flexors for men and women with a wide range of age

The present study examined the age-related changes in muscle thickness (MT) and volume (MV) of elbow flexors and developed a prediction equation of the MV based on the MT applicable to men and women with a wide range of age. The MT and MV were determined from a single ultrasonographic image and multiple magnetic resonance imaging scans, respectively, in 72 men and 75 women aged 19-77 year. As a result of examining the age-MT and age-MV relationships by calculation of partial correlation coefficients with the control variable of gender, MV was decreased with aging whereas the corresponding decline in MT was not significant. The subjects were randomly separated into either a validation (38 men and 42 women) or a cross-validation (34 men and 33 women) group, and a multiple regression equation to estimate MV using not only MT but also upper arm length (L), age and gender as independent variables [MV (cm(3)) = 60.8 x MT (cm) + 6.48 x L (cm) - 0.709 x age (year) + 51.4 x gender (0 women, 1 men) - 187.4] was validated and cross-validated. Thus, the prediction equation for MV of elbow flexors newly developed was shown to be applicable to men and women with a wide range of age.

Positive energy balance is associated with accelerated muscle atrophy and increased erythrocyte glutathione turnover during 5 wk of bed rest

BACKGROUND

Physical inactivity is often associated with positive energy balance and fat gain.

OBJECTIVE

We aimed to assess whether energy intake in excess of requirement activates systemic inflammation and antioxidant defenses and accelerates muscle atrophy induced by inactivity.

DESIGN

Nineteen healthy male volunteers were studied before and at the end of 5 wk of bed rest. Subjects were allowed to spontaneously adapt to decreased energy requirement (study A, n = 10) or were provided with an activity-matched diet (study B, n = 9). Groups with higher (HEB) or lower (LEB) energy balance were identified according to median values of inactivity-induced changes in fat mass (DeltaFM, assessed by bioelectrical impedance analysis).

RESULTS

In pooled subjects (n = 19; median DeltaFM: 1.4 kg), bed rest-mediated decreases in fat-free mass (bioelectrical impedance analysis) and vastus lateralis thickness (ultrasound imaging) were significantly greater (P < 0.03) in HEB(AB) (-3.8 +/- 0.4 kg and -0.32 +/- 0.04 cm, respectively) than in LEB(AB) (-2.3 +/- 0.5 kg and -0.09 +/- 0.04 cm, respectively) subjects. In study A (median DeltaFM: 1.8 kg), bed rest-mediated increases in plasma leptin, C-reactive protein, and myeloperoxidase were greater (P < 0.04) in HEB(A) than in LEB(A) subjects. Bed rest-mediated changes of glutathione synthesis rate in eythrocytes (l-[3,3-(2)H(2)]cysteine incorporation) were greater (P = 0.03) in HEB(A) (from 70 +/- 19 to 164 +/- 29%/d) than in LEB(A) (from 103 +/- 23 to 84 +/- 27%/d) subjects.

CONCLUSIONS

Positive energy balance during inactivity is associated with greater muscle atrophy and with activation of systemic inflammation and of antioxidant defenses. Optimizing caloric intake may be a useful strategy for mitigating muscle loss during period of chronic inactivity.

Body composition and fitness during strength and/or endurance training in older men

PURPOSE

This study examined adaptations in body composition and physical fitness during a 21-wk strength and/or endurance training period in 40- to 65-yr-old men. We also compared the usefulness of different methods for the analysis of body composition to detect training-induced adaptations.

METHODS

Fifty-three men were randomized into the endurance training (E: N = 14), strength training (S: N = 13), combined strength and endurance training (SE: N = 15), or control (C: N = 11) groups. S and E trained 2 and SE 2 x 2 times a week for strength and endurance.

RESULTS

Percentage of fat (fat%) decreased (5-8%) similarly in all training groups. Fat% measured by DXA at baseline and its change correlated with those recorded by bioimpedance (r = 0.90 and 0.66), skinfolds (r = 0.80 and 0.78), and waistline (r = 0.84 and 0.74). Lean mass in legs (DXA) increased only in S (2.0 +/- 1.5%, P < 0.001), but the thickness of vastus lateralis and intermedius measured by ultrasound increased (7-11%) in all training groups, and that of triceps brachii increased in S (22%) and SE (20%). Maximal concentric force increased significantly in S, SE, and E (by 22, 23, and 7%), and maximal oxygen uptake increased in both E (11%) and SE (11%).

CONCLUSIONS

Waist circumference and skinfold thickness seem to reasonably assess changes in percent body fat during training. However, only DXA was capable to separate small differences between the groups in training-induced changes in lean body mass. Combined strength and endurance training is of greater value than either alone in optimizing body composition or improving physical fitness in older men.

Association between sonographic morphology of vastus medialis obliquus and patellar alignment in patients with patellofemoral pain syndrome

STUDY DESIGN

Descriptive, correlational, anatomical laboratory study.

OBJECTIVES

To investigate the association between the morphology of the vastus medialis obliquus (VMO) and patellar alignment in patients with patellofemoral pain syndrome (PFPS).

BACKGROUND

It has long been presumed that PFPS results from patellar malalignment. Strengthening of the VMO has been suggested as an intervention to treat individuals with PFPS, through correction of abnormal patellar tracking. However, the exact role of the VMO in the etiology and treatment of PFPS is not clear.

METHODS AND MEASURES

This study included 58 patients with PFPS, of which 31 had bilateral involvement. A total of 89 knees were imaged with a Merchant's view radiograph at 45 degrees of knee flexion to measure patellar alignment consisting of patellar tilt and congruence angles. Those 89 knees were also examined with sonography with the knee in full extension and quadriceps relaxed to measure VMO morphology and additional characteristics such as insertion level, insertion ratio, fiber angle, and volume. The level of association between radiographic and sonographic measurements was explored to determine any relationship between patellar alignment and morphology of the VMO.

RESULTS

The patellar tilt angle was negatively correlated with the VMO insertion level (r = -.58, P<.05), insertion ratio (r= -.52, P<.05), and volume (r = -.45, P<.05). In addition, the patellar congruence angle was negatively correlated with the VMO fibers angle (r = -.23, P<.05).

CONCLUSIONS

This study showed that some aspects of VMO morphology, measured in full knee extension with the quadriceps relaxed, were associated with patellar alignment measured with the knee at 45 degrees of flexion. Whether or not VMO morphology serves as a predictor of patella alignment with the knee extended should be the focus of future investigations.

Rehabilitative ultrasound imaging of the lower trapezius muscle: technical description and reliability

STUDY DESIGN

Exploratory and reliability study.

BACKGROUND

Shoulder dysfunction is common and often difficult to diagnose and treat. The trapezius muscle is an important stabilizer and primary mover of the scapula. The potential use of rehabilitative ultrasound imaging (RUSI) to evaluate scapular muscle function warrants investigation.

OBJECTIVES

To establish a procedure for imaging the thickness of the lower trapezius muscle and to examine reliability within and among investigators.

METHODS

In 16 asymptomatic subjects (12 female, 4 male), aged 20 to 41 years, 3 investigators used RUSI to measure the thickness of the left lower trapezius muscle with the subject at rest in prone. Investigator 1 took 3 images on each of 2 days, while the other 2 investigators took 2 images each on the second day. All measurements of lower trapezius muscle thickness were made off-line, at a point 3 cm lateral to the lateral edge of the spinous processes. To also obtain within-scan reliability, 1 image taken by investigator 1, once displayed on the scanner's screen, was measured 3 times. Investigator 1 also measured lower trapezius muscle thickness 1 cm medial to this site. Reliability was examined using intraclass correlation coefficients (ICC) and the Bland and Altman plot.

RESULTS

The intrarater within-scan reliability at the lateral site was ICC3.3 = 0.99 (95% CI: 0.98 to 1.0). The intrarater between-scan reliability (within-day) at the lateral site, medial site, and combined sites (mean of medial and lateral) were ICC3.3 = 0.96 (95% CI: 0.90 to 0.98), ICC3.2 = 0.90 (95% CI: 0.78 to 0.96), and ICC3.2 = 0.99 (95% CI: 0.99 to 1.0), respectively. Intrarater (between-day) reliability was good for the lateral site and combined sites (ICC3.3 = 0.91, 95% CI: 0.74 to 0.96, and ICC3.3 = 0.90, 95% CI: 0.70 to 0.96, respectively) and moderate for the medial site (ICC3.3 = 0.89, 95% CI: 0.68 to 0.96). Interrater reliability (among investigators) was also moderate (ICC2.2 = 0.88, 95% CI: 0.73 to 0.96). Mean lower trapezius muscle thickness was approximately 3.1 mm (SD, 0.8 mm).

CONCLUSION

Thickness of the lower trapezius muscle can be measured reliably with RUSI.

Calf muscle volume estimates: implications for botulinum toxin treatment?

An optimal botulinum toxin dose may be related to the volume of the targeted muscle. We investigated the suitability of using ultrasound and anthropometry to estimate gastrocnemius and soleus muscle volume. Gastrocnemius and soleus muscle thickness was measured in 11 cadaveric human legs, using ultrasound. Lower leg length was tape-measured. Muscle volume was determined by water displacement of the dissected muscles. Simple and multiple regression analyses, using muscle thickness and lower leg length as independent variables, were performed to establish muscle volume prediction equations from the muscle volume measured by water displacement. Validating the equations based on simple regression analyses resulted in a correlation (r2) of 0.373 and 0.518 (P < 0.047), and a standard error of the estimate of 24.4 cm3 (11.7% of the measured mean muscle volume) and 33.2 cm3 (12.7%) for the gastrocnemius and soleus muscles, respectively. The corresponding values for the multiple regression analyses were an r2 of 0.497 and 0.650 (P < 0.017), and a standard error of the estimate of 21.9 cm3 (10.5%) and 28.4 cm3 (10.8%) for the gastrocnemius and soleus muscles, respectively. It seems possible to estimate the volume of individual plantar flexor muscles using ultrasound and anthropometry. This possibility should be investigated further in living humans.

The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans

Strength training is an important component in sports training and rehabilitation. Quantification of the dose-response relationships between training variables and the outcome is fundamental for the proper prescription of resistance training. The purpose of this comprehensive review was to identify dose-response relationships for the development of muscle hypertrophy by calculating the magnitudes and rates of increases in muscle cross-sectional area induced by varying levels of frequency, intensity and volume, as well as by different modes of strength training. Computer searches in the databases MEDLINE, SportDiscus and CINAHL were performed as well as hand searches of relevant journals, books and reference lists. The analysis was limited to the quadriceps femoris and the elbow flexors, since these were the only muscle groups that allowed for evaluations of dose-response trends. The modes of strength training were classified as dynamic external resistance (including free weights and weight machines), accommodating resistance (e.g. isokinetic and semi-isokinetic devices) and isometric resistance. The subcategories related to the types of muscle actions used. The results demonstrate that given sufficient frequency, intensity and volume of work, all three types of muscle actions can induce significant hypertrophy at an impressive rate and that, at present, there is insufficient evidence for the superiority of any mode and/or type of muscle action over other modes and types of training. Tentative dose-response relationships for each variable are outlined, based on the available evidence, and interactions between variables are discussed. In addition, recommendations for training and suggestions for further research are given.

The validity of estimating quadriceps volume from single MRI cross-sections in young men

Muscle size is often reported as a single anatomical cross-sectional area (ACSA), rather than volume measured with contiguous MRI scans. However, a single ACSA may provide an inadequate estimate of muscle mass. Therefore, we investigated whether quadriceps muscle volume can be adequately estimated from a single ACSA. In 18 adult males we derived regression equations from which estimates of volume were made. These equations were based on the direct assessment of volume using 11 transverse-plane MRI scans along the entire length of the femur (the gold standard). We estimated volume based on single scans at 40, 50 and 60% of femur length (from the distal end). All estimates of quadriceps volumes were highly correlated to the measured volume and demonstrated a low level of error. R (2) = 0.84, 0.93, 0.90 (all P < 0.01), standard error of estimate (SEE) = 26.8 +/- 5.2, 12.5 +/- 5.4 and 9.9 +/- 5.7%, for single scans taken at 40, 50 and 60% of femur length respectively. In comparison, when volume was estimated using multiple MRI scans corresponding to the maximum ACSA of each muscle the estimate was even better [R (2) = 0.95 (P < 0.01) and SEE = 4.5 +/- 2.7%]. Substituting ACSA from a single MRI scan at 60% of femur length into a previously determined regression equation allows for an estimation of muscle volume with a 10% error of estimate.

Calf muscle-tendon properties and postural balance in old age

We tested the hypothesis that compromised postural balance in older subjects is associated with changes in calf muscle-tendon physiological and mechanical properties. Trial duration and center of pressure (COP) displacements were measured in 24 younger (aged 24+/-1 yr), 10 middle-aged (aged 46+/-1 yr), and 36 older (aged 68+/-1 yr) healthy subjects under varying levels of postural difficulty. Muscle-tendon characteristics were assessed by dynamometry, twitch superimposition, and ultrasonography. In tandem and single-leg stances, trial duration decreased (<or=65% lower, P<0.001) and COP displacements increased (<or=90% higher, P<0.05) with age. Muscle strength, size, activation capacity, and tendon mechanical properties decreased with age by 55, 13, 13, and 36-48%, respectively (P<0.05). Regressions with these parameters and balance indexes were significant (P<0.05) for single-leg and tandem (0.69<r2<0.90) postures only, indicating that the age-related changes in muscle-tendon characteristics may explain the majority of the variance in balance performance during tasks more difficult than habitual bipedal stance.

Differences in size, strength, and power of upper and lower body muscle groups in young and older men

We compared muscle thickness, torque, normalized torque (torque/muscle thickness), and power at 1.05 rad/s and 3.14 rad/s in flexor and extensor muscles of the elbow and knee, and in ankle plantar flexors in young (n=22, 18-31 years) and older (n=28, 59-76 years) men. Young men had greater muscle thickness for all muscle groups (p<.01), except elbow extensors, which were similar to older men. Young men had greater torque and power at both velocities for all muscle groups (p<.01), and greater normalized torque at both velocities for the elbow extensors and knee flexors and at the fast velocity for knee extensors. Relative to young mean values, muscle thickness, and torque, normalized torque, and power in the older group were most affected for lower-body measurements, especially at the fast velocity. Torque, normalized torque, and power (especially at fast velocities), and muscle thickness in the lower body are affected more by aging than are upper body measures in men.

A predictive model of moment-angle characteristics in human skeletal muscle: application and validation in muscles across the ankle joint

In the present work, a generic model for the prediction of moment-angle characteristics in individual human skeletal muscles is presented. The model's prediction is based on the equation M = V x Lo(-1)sigma c cos phi x d, where M, V, and Lo are the moment-generating potential of the muscle, the muscle volume and the optimal muscle fibre length, respectively, and sigma, phi and d are the stress-generating potential of the muscle fibres, their pennation angle and the tendon moment arm length, respectively, at any given joint angle. The input parameters V, Lo, sigma, phi and d can be measured or derived mechanistically. This eliminates the common problem of the necessity to estimate one or more of the input parameters in the model by fitting its outcome to experimental results often inappropriate for the function modelled. The model's output was validated by comparisons with the moment-angle characteristics of the gastrocnemius (GS) and tibialis anterior (TA) muscles in six men, determined experimentally using voluntary contractions at several combinations of ankle and knee joint angles for the GS muscle and electrical stimulation for the TA muscle. Although the model predicted realistically the pattern of moment-angle relationship in both muscles, it consistently overestimated the GS muscle M and consistently underestimated the TA muscle M, with the difference gradually increasing from dorsiflexion to plantarflexion in both cases. The average difference between predicted and measured M was 14% for the GS muscle and 10% for the TA muscle. Approximating the muscle fibres as a single sarcomere in both muscles and failing to achieve complete TA muscle activation by electrical stimulation may largely explain the differences between theory and experiment.

An ultrasonic methodology for muscle cross section measurement to support space flight

The number one priority for any manned space mission is the health and safety of its crew. The study of the short and long term physiological effects on humans is paramount to ensuring crew health and mission success. One of the challenges associated in studying the physiological effects of space flight on humans, such as loss of bone and muscle mass, has been that of readily attaining the data needed to characterize the changes. The small sampling size of astronauts, together with the fact that most physiological data collection tends to be rather tedious, continues to hinder elucidation of the underlying mechanisms responsible for the observed changes that occur in space. Better characterization of the muscle loss experienced by astronauts requires that new technologies be implemented. To this end, we have begun to validate a 360 degree ultrasonic scanning methodology for muscle measurements and have performed empirical sampling of a limb surrogate for comparison. Ultrasonic wave propagation was simulated using 144 stations of rotated arm and calf MRI images. These simulations were intended to provide a preliminary check of the scanning methodology and data analysis before its implementation with hardware. Pulse-echo waveforms were processed for each rotation station to characterize fat, muscle, bone, and limb boundary interfaces. The percentage error between MRI reference values and calculated muscle areas, as determined from reflection points for calf and arm cross sections, was -2.179% and +2.129%, respectively. These successful simulations suggest that ultrasound pulse scanning can be used to effectively determine limb cross-sectional areas. Cross-sectional images of a limb surrogate were then used to simulate signal measurements at several rotation angles, with ultrasonic pulse-echo sampling performed experimentally at the same stations on the actual limb surrogate to corroborate the results. The objective of the surrogate sampling was to compare the signal output of the simulation tool used as a methodology validation for actual tissue signals. The disturbance patterns of the simulated and sampled waveforms were consistent. Although only discussed as a small part of the work presented, the sampling portion also helped identify important considerations such as tissue compression and transducer positioning for future work involving tissue scanning with this methodology.