Measurement of anterior tibial muscle size using real-time ultrasound imaging

Review of Reliable and Valid Noninvasive Tools for the Diagnosis of Chronic Exertional Compartment Syndrome

Background

Currently, invasive dynamic intracompartmental pressure (ICP) measurements are considered the gold standard for diagnosis of chronic exertional compartment syndrome (CECS). During recent years, different noninvasive imaging modalities have been presented as a possible replacement for ICP measurement.

Purpose

To provide an overview of the current state of evidence and possibilities regarding noninvasive diagnostic methods for CECS.

Study Design

Scoping review; Level of evidence, 4.

Methods

The PubMed (MEDLINE) and Embase databases were searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Full-text articles were included if they reported on noninvasive diagnostic methods for CECS, included ≥5 patients with CECS, and were published between 1994 and 2022. Articles not written in English were excluded. Systematic reviews, letters to the editor, and case reports were not eligible for inclusion. Out of 961 articles identified in the initial search, 25 studies (N = 1257 participants) were included. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-Comparative (QUADAS-C) tool for comparative studies and the QUADAS-2 tool for noncomparative studies. Narrative synthesis was used to present results.

Results

The level of evidence for the 25 studies ranged from 2 to 4. Four studies were classified as having a low risk of bias, 21 studies were classified as being at risk of bias. The following noninvasive diagnostic tools for CECS were reported: magnetic resonance imaging/diffusion tensor imaging (n = 8), near-infrared spectroscopy (n = 6), electromyography (n = 4), single-photon emission computed tomography (n = 5), ultrasound (n = 2), myotonometry (n=1) and predictive clinical model (n = 1). There was insufficient evidence in the literature to support the use of any of these noninvasive diagnostic tools as a gold standard for CECS.

Conclusion

Despite the need to replace the controversial use of ICP for the diagnosis of CECS, our review indicated a lack of validity on all discussed noninvasive diagnostic tools as a replacement.

Impact of Body Mass Index on Muscle Strength, Thicknesses, and Fiber Composition in Young Women

High body mass index (BMI) may influence muscle strength, muscle thickness (Mtk), and fiber composition. We evaluated these parameters in 31 and 27 women grouped in non-oral contraceptive (non-OC) groups and OC groups, respectively, and further divided them into groups based on BMI: BMI_low, BMI_norm, and BMI_high. Maximum isometric force (F_max), Mtk, and the relative percentage of muscle fiber composition (%) were examined in both groups. F_max and Mtk values were significantly greater in the BMI_high than the BMI_low within the OC group. However, there was no significant difference in the non-OC group. BMI_low and BMI_norm groups showed a difference in the distribution of muscle fiber types 1 and 2 with almost the same proportions in both non-OC and OC groups. However, the BMI_high group showed a difference in the distribution of muscle fiber types 1 and 2, with type 1 about 18.76% higher in the non-OC group. Contrastively, type 2 was about 34.35% higher in the OC group. In this study, we found that there was a significant difference in F_max and Mtk according to the BMI level in the OC group, but no significant difference was found in the non-OC group. Moreover, the distribution of type 2 muscle fibers tended to be higher in the OC group of BMI_high, although the sample size was small. Therefore, although no significant difference of F_max and Mtk was found according to BMI level in the non-OC group in this study, the increase in BMI level appeared to be more associative of muscle strength in the OC group. Based on the present results, future studies are needed that consider the BMI level as well as the presence or absence of OC in future research about women's muscle strength.

Effects of growth on muscle architecture of knee extensors

This study aimed to investigate the effects of growth on the muscle architecture of knee extensors. The present study included 123 male children and adolescents. The muscle thicknesses of the rectus femoris (RF) and vastus intermedius (VI), and pennation angles and fascicle lengths of RF were measured in three regions using ultrasonography technique at rest. The relative muscle thickness was calculated by dividing the absolute muscle thickness by body mass^1/3 . The years from age at peak height velocity were estimated for each participant, and used as a maturity index. The maturity index was significantly correlated with the relative muscle thicknesses of RF and VI in all regions. The slope of the relationship between the maturity index and the relative muscle thickness did not differ significantly between muscles within the same region or between regions within the individual muscles. The fascicle length and pennation angle of RF were significantly correlated with the absolute muscle thickness in all regions. In the proximal RF region, the coefficient of correlation between the muscle thickness and fascicle length was significantly greater than that between the muscle thickness and pennation angle. The present results showed that growth changes in muscle thickness were uniform between and within RF and VI. Our findings suggest that growth changes in the muscle thickness of RF depend on the increases in both pennation angle and fascicle length, but their contributions to the growth of muscle thickness differ among muscle regions.

Effects of oral contraceptive use on muscle strength, muscle thickness, and fiber size and composition in young women undergoing 12 weeks of strength training: a cohort study

BACKGROUND

It is suspected that hormonal fluctuations during menstruation may cause different responses to strength training in women who use oral contraceptives (OC) versus those who do not. However, previous studies that investigated the existence of such differences produced conflicting results. In this study, we hypothesized that OC use has no effect on muscle strength and hypertrophy among women undergoing strength training. Thus, we compared the differences in muscle strength and thickness among women who used OCs and those who did not.

METHODS

We investigated the influence of OC use on muscle strength (Fmax), muscle thickness (Mtk), type 1-to-type 2 muscle fiber (NO) ratio, muscle fiber thickness (MFT), and nuclear-to-fiber (N/F) ratio. Seventy-four healthy young women (including 34 who used OCs and 40 who did not) underwent 12 weeks of submaximal strength training, after which Fmax was evaluated using a leg-press machine with a combined force and load cell, while Mtk was measured using real-time ultrasonography. Moreover, the NO ratio, MFT, and N/F ratio were evaluated using muscle needle biopsies.

RESULTS

Participants in the non-OC and OC groups experienced increases in Fmax (+ 23.30 ± 10.82 kg and + 28.02 ± 11.50 kg respectively, p = 0.073), Mtk (+ 0.48 ± 0.47 cm2 and + 0.50 ± 0.44 cm2 respectively, p = 0.888), Fmax/Mtk (+ 2.78 ± 1.93 kg/cm2 and + 3.32 ± 2.37 kg/cm2 respectively, p = 0.285), NO ratio (type 2 fibers: + 1.86 ± 6.49% and - 4.17 ± 9.48% respectively, p = 0.169), MFT (type 2 fibers: + 7.15 ± 7.50 µm and + 4.07 ± 9.30 µm respectively, p = 0.435), and N/F ratio (+ 0.61 ± 1.02 and + 0.15 ± 0.97 respectively, p = 0.866) after training. There were no significant differences between the non-OC and OC groups in any of these parameters (p > 0.05).

CONCLUSIONS

The effects of 12 weeks of strength training on Fmax, muscle thickness, muscle fiber size, and composition were similar in young women irrespective of their OC use.

Ultrasound Imaging Is Reliable for Tibialis Posterior Size Measurements

OBJECTIVES

The tibialis posterior (TP) is a vital muscle for controlling the medial longitudinal arch of the foot during weight-bearing activities. Dysfunction of this muscle is associated with a variety of pathologic conditions; thus, it is important to reliably assess its morphologic characteristics. Ultrasound (US) has been used to assess characteristics of TP tendons but not the muscle cross-sectional area (CSA). The purpose of this study was to establish a reliable US technique to measure the TP CSA and thickness.

METHODS

Twenty-three healthy volunteers participated. We evaluated the CSA and thickness at 4 measurement locations (anterior and posterior views at both 30% and 50% of the shank length).

RESULTS

The participants included 12 female and 11 male volunteers (mean age ± SD, 31.23 ± 14.93 years). Excellent reliability was seen for the CSA and thickness at all locations (intraclass correlation coefficients, 0.988-0.998). Limits of agreement (LoA) and standard errors of the measurement (SEMs) were slightly lower at the 30% locations (LoA at 30%, 4.6-9.2; LoA at 50%, 6.4-9.7; SEM at 30%, 0.03-0.05; SEM at 50%, 0.04-0.07). Strong correlations were seen between anterior and posterior measurements of the CSA (30%, r = 0.99; P < .0001; 50%, r = 0.94; P < .0001) and thickness (30%, r = 0.98; P < .0001; 50%, r = 0.95; P = .0001).

CONCLUSIONS

Based on these results, the TP can be measured accurately with US at any of the tested locations. Due to the ease of collection and the quality of the data, we recommend the anterior view at 30% of the shank length to measure the CSA. The ability to assess muscle size of the TP will aid in a variety of medical and research applications.

Interrater and Intrarater Reliability of a Handheld Myotonometer in Measuring Mechanical Properties of the Neck and Orofacial Muscles

OBJECTIVE

The purpose this study was to investigate the reliability of a handheld myotonometer in measuring the mechanical properties of the neck and orofacial muscles in asymptomatic individuals.

METHODS

The study included 16 healthy participants. The mechanical properties (frequency, decrement, stiffness, relaxation time, and creep) of the selected muscles were measured with a MyotonPRO myotonometer (Mumeetria Ltd, Tallinn, Estonia). The sternocleidomastoid, upper trapezius, cervical extensor, and masseter muscles were selected to determine the reliability of the device. Measurements were performed by 2 examiners to determine interrater reliability; for intrarater reliability, an examiner repeated the measurements 1 week after the first measurements.

RESULTS

The results revealed moderate to excellent intrarater and interrater reliability (intraclass correlation coefficients: 0.50-0.95) in measuring muscle mechanic properties. The standard error of measurement in the tested muscles ranged from 0.3 to 0.8 Hz for frequency, from 7.4 to 20.9 N/m for stiffness, from 0.1 to 0.2 for decrement, and from 0.8 to 1.4 ms for relaxation time. The minimum detectable change ranged from 0.8 to 2.2 Hz for frequency, from 20.5 to 57.9 N/m for stiffness, from 0.2 to 0.6 for decrement, from 2.2 to 3.9 ms for relaxation time, and from 0.2 to 0.3 for creep. In addition, the coefficients of variation were below 9.1% for all the assessed parameters.

CONCLUSION

The obtained results demonstrate that the MyotonPRO device is a reliable and repeatable tool to quantify the frequency, stiffness, decrement, relation time, and creep of the neck and orofacial muscles in asymptomatic individuals.

Relationship between Muscle Cross-Sectional Area by MRI and Muscle Thickness by Ultrasonography of the Triceps Surae in the Sitting Position

The purpose of this study was to determine the differences in the muscle cross-sectional area (MCSA) of the triceps surae in the supine and sitting positions using magnetic resonance imaging (MRI), and the relationship between the MCSA of the triceps surae in the sitting position and muscle thickness (MT), assessed using MRI and ultrasonography, respectively. This study included 16 healthy young male participants. The measurement positions were 90° flexion of the knee joint and neutral position of the ankle joint in the sitting or supine positions. Using an open-configuration MRI system with a vertical gap and ultrasonography, we measured the MCSA and MT of the soleus muscle and the medial and lateral heads of the gastrocnemius muscle at three selected locations in the ventral part of the muscle. As a result, the 50% portion of the soleus muscle and the 25% and 50% portions of the gastrocnemius medial and lateral heads were higher in the sitting position than in the supine position. Furthermore, only 50% of the gastrocnemius medial head showed a correlation between the MCSA and MT. When using the MT of the triceps surae as an indicator of muscle volume in the sitting position, the muscle site should be considered.

Use of Cine Loops and Structural Landmarks in Ultrasound Image Processing Improves Reliability and Reduces Error in the Assessment of Foot and Leg Muscles

OBJECTIVES

Foot and leg muscle strength and size are crucial to proper function. It is important to assess these characteristics reliably. Our primary objective was to compare the measurement of still images to cine loops. The secondary purpose was to determine interoperator and intraoperator reliability between operators of different experience levels using video clips and internal and external landmarks.

METHODS

Twelve healthy volunteers participated in our study. Internal (navicular tuberosity) and external (lateral leg length at 30% and 50% from the knee joint line) landmarks were used. Two operators each captured and later measured still and cine loop images of selected foot and leg muscles.

RESULTS

The 12 participants included 8 male and 4 female volunteers (mean age ± SD, 23.5 ± 1.9 years). Good to excellent intraoperator and interoperator reliability was seen (intraclass correlation coefficient range of 0.946-0.998). The use of cine loops improved the intraclass correlation coefficients for both intraoperator and interoperator reliability (0.5%-4% increases). The use of cine loops decreased the intraoperator standard error of the measurement and limits of agreement of the novice operator (decreases of 45%-73% and 24%-51%, respectively), and these became comparable to those of experienced operators using still images. The interoperator standard errors of the measurement dropped by 42% to 53%, whereas the limits of agreement dropped by 27% to 40%. No substantial changes were noted in the tibialis anterior across reliability metrics.

CONCLUSIONS

Improved protocols that take advantage of using internal bony landmarks and cine loops during both the image-gathering and measurement processes improve the reliability of research examining muscle size changes in the lower leg or foot associated with muscle changes due to exercise, injury, disuse, or disease.

Relationship between ultrasound muscle thickness and MRI-measured muscle cross-sectional area in the forearm: a pilot study

Previous studies have investigated the relationship between ultrasound-measured muscle thickness (MT) and individual muscle cross-sectional area (CSA); however, the forearm muscle had not yet been studied. The purpose of this study was to examine the relationship between forearm MT by ultrasound and the muscle CSA of the forearm obtained by magnetic resonance imaging (MRI). Ten young and middle-aged adults had both ultrasound and MRI measurements at 30% the distance from the styloid process of the ulna to the head of the radius. Handgrip strength (HGS) was also measured. Strong correlations (P<0·001) were observed between MRI-measured muscle CSA (total and flexor and extensor components) and MT-ulna (ranged r = 0·937-0·946) and MT-radius (ranged r = 0·884-0·891). HGS was also correlated (P<0·001) with forearm MT (MT-ulna, r = 0·877; MT-radius, r = 0·852) and MRI-measured muscle CSA (flexor CSA, r = 0·910; extensor CSA, r = 0·923). Our results suggest that forearm MT is closely associated with MRI-measured forearm muscle CSA in young and middle-aged adults and suggest that ultrasound-measured forearm muscle thickness may be a useful variable for evaluating muscle CSA and function in the forearm.

Shear Wave Elastography Is a Reliable and Repeatable Method for Measuring the Elastic Modulus of the Rectus Femoris Muscle and Patellar Tendon

OBJECTIVES

The purpose of this study was to determine intraobserver, interobserver, and inter-day reliability levels for stiffness measurements of the patellar tendon and rectus femoris muscle using shear wave elastography (SWE).

METHODS

This study was conducted on 12 healthy male individuals. Two examiners measured mean shear wave velocity values of the patellar tendons and rectus femoris muscles of both extremities using a 9L4 (4-9 MHz) transducer and an Acuson S3000 ultrasound system (Siemens Medical Solutions, Mountain View, CA). The elasticity images were acquired by the Virtual Touch tissue imaging quantification technique (Siemens Medical Solutions). Measurements were repeated 20 minutes and 1 week after the first measurements. The reliability of SWE measurements was assessed by means of the intraclass correlation coefficient (ICC).

RESULTS

The 12 participants ranged in age from 19 to 33 years (mean age ± SD, 25.33 ± 4.56 years). For the patellar tendon stiffness measurements with SWE, it was found that intraobserver reliability (ICC, 0.91-0.92) and interday reliability (ICC, 0.81-0.83) were excellent, and interobserver reliability (ICC, 0.71) was good. For the rectus femoris muscle stiffness measurements with SWE, it was found that the intraobserver reliability (ICC, 0.93-0.94), interday reliability (ICC, 0.81-0.91), and interobserver reliability (ICC, 0.95) were perfect.

CONCLUSIONS

Shear wave elastography using the Virtual Touch tissue imaging quantification technique is a reliable and repeatable technique for patellar tendon and rectus femoris stiffness measurements according to intraobserver, interday, and interobserver ICC values.

Enhanced Corticospinal Excitability and Volitional Drive in Response to Shortening and Lengthening Strength Training and Changes Following Detraining

There is a limited understanding of the neurological adaptations responsible for changes in strength following shortening and lengthening resistance training and subsequent detraining. The aim of the study was to investigate differences in corticospinal and spinal responses to resistance training of the tibialis anterior muscle between shortening or lengthening muscle contractions for 4 weeks and after 2 weeks of detraining. Thirty-one untrained individuals were assigned to either shortening or lengthening isokinetic resistance training (4 weeks, 3 days/weeks) or a non-training control group. Transcranial magnetic stimulation and peripheral nerve stimulation (PNS) were used to assess corticospinal and spinal changes, respectively, at pre-, mid-, post-resistance training and post detraining. Greater increases changes (P < 0.01) in MVC were found from the respective muscle contraction training. Motor evoked potentials (expressed relative to background EMG) significantly increased in lengthening resistance training group under contraction intensities ranging from 25 to 80% of the shortening and lengthening contraction intensity (P < 0.01). In the shortening resistance training group increases were only seen at 50 and 80% of both contraction type. Volitional drive (V-wave) showed a greater increase following lengthening resistance training (57%) during maximal lengthening contractions compared to maximal shortening contractions following shortening resistance training (23%; P < 0.001). During the detraining period MVC and V-wave did not change (P > 0.05), although MEP amplitude decreased during the detraining period (P < 0.01). No changes in H-reflex were found pre to post resistance training or post detraining. Modulation in V-wave appeared to be contraction specific, whereby greatest increases occurred following lengthening resistance training. Strength and volitional drive is maintained following 2 weeks detraining, however corticospinal excitability appears to decrease when the training stimulus is withdrawn.

Surgical Treatment of Chronic Exertional Compartment Syndrome in Pediatric Patients

BACKGROUND

Chronic exertional compartment syndrome (CECS) is a cause of leg pain in running athletes and is treated with fasciotomy after failure of nonoperative management. CECS is being seen with increased frequency in younger patients. The demographics and outcomes of fasciotomy for CECS in pediatric patients, including risk factors for treatment failure, have not been described.

PURPOSE

To describe characteristics of pediatric patients with CECS and determine surgical outcomes of the condition in this population.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review was performed for patients 18 years and younger treated surgically for CECS with compartment release at a single institution from 1995 to 2014. Demographic and condition characteristics, operative procedure, postoperative course, and clinical outcomes were recorded for 286 legs of 155 patients. Compartment pressure testing using the Pedowitz criteria confirmed the diagnosis in all patients.

RESULTS

A total of 155 patients were included in the study (average patient age at presentation, 16.4 ± 1.38 years); 136 (88%) were female. All 155 patients presented with leg pain; of these patients, 8 (5%) also had neurologic symptoms, and 131 (85%) presented with bilateral symptoms requiring bilateral compartment release. Symptoms were chronic in nature, with duration over 1 year in 63% of patients. The primary sport was most commonly reported as running (25%), soccer (23%), or field hockey (12%); 50% of patients were multisport athletes. Of 286 legs, 138 (48%) had only anterior and/or lateral compartments released, while 84 (29.4%) had all 4 compartments released. Documented return to sport was seen in 79.5% of patients. Outcomes analysis was performed for 250 of 286 legs. Of these 250 legs, 47 (18.8%) had recurrent CECS requiring reoperation at a median of 1.3 years (interquartile range, 0.8-3.5) after initial compartment release. For each additional month between presentation and release, the odds of recurrence decreased by 12% (P = .04). Legs with only anterior and/or lateral compartment released had 3.4 times (95% CI, 1.29-9.14) the odds of reoperation compared with legs that had all 4 compartments released (P = .01). Twenty-eight of 250 legs (11.2%) had wound issues that resolved with nonoperative management. No wounds required repeat surgical management.

CONCLUSION

CECS in pediatric patients most commonly occurs in adolescent females participating in running sports. Fasciotomy results in a 79.5% return-to-sports rate. Recurrence occurs in 18.8% of patients, more commonly in patients undergoing anterior and lateral release only.

Symmetry of anterior tibial muscle size measured by real-time ultrasound imaging in young females

The between-limb symmetry of anterior tibial muscle size was examined in 40 healthy females, aged 18-35 years (20.7 ± 3.9). Real-time ultrasound imaging was used to measure the cross-sectional area (CSA) of the muscle group. With the subject half-lying, bilateral scans were taken and measurements of CSA were made by tracing the muscle group outline using an onscreen electronic calliper. On each scan, two CSA measurements were made and the mean of the two measurements was used in the analysis. Between-side comparisons were made by expressing the CSA of the smaller muscle as a percentage of that of the larger muscle and the mean, standard deviation and range for the 40 subjects were calculated. The paired t-test was used to compare the raw data between-sides, i.e. larger versus smaller muscle. The smaller muscle was approximately 93% of the size of the larger muscle with a mean difference of 7.2% ± 5% and a range of 0.1-20%. The differences between the raw values for CSA were significantly different ( p < 0.001). The degree of symmetry of anterior tibial muscle size has been documented in a group of normal young females using real-time ultrasound scanning, which could be used to examine wasting in patients with unilateral leg injuries or pathology. The degree of normal symmetry for other subject groups of both sexes and different ages needs to be documented.

Reliability of ultrasound elastography for the quantification of transversus abdominis elasticity

Background

The transversus abdominis (TrA), which is considered to be involved in controlling spinal stability, is covered by two muscles (i.e. the external and internal oblique muscles) as well as subcutaneous fat. Therefore, there were doubts about whether it was possible to perform highly reliable measurements of muscle elasticity.

Purpose

To investigate the reliability of ultrasound elastography for the quantification of elasticity of the TrA.

Material and Methods

A skilled and an unskilled operator of ultrasound elastography measured TrA elasticity in 10 healthy men (age, 24 ± 4 years; height, 172.0 ± 5.2 cm; weight, 72.3 ± 12.0 kg) in the supine position. The tests were repeated six times; of the six measured values, a group of four measurements showing the lowest coefficient of variation (CV) was adopted and the mean values were used for further analysis. This procedure was repeated twice on each participant on two different days.

Results

The intra-class correlation coefficients (ICCs) between days for skilled and unskilled operators were 0.86 (P < 0.00) and 0.59 (P = 0.02), respectively, and the CVs were 8.7% and 13.8%, respectively. The ICCs between operators and CVs were in the range of 0.56–0.57 (P = 0.02–0.03) and 13.5–15.5%, respectively. No systematic error was found for any comparison.

Conclusion

The reliabilities of the skilled and unskilled operators were high and moderate, respectively.

Morphological and functional relationships with ultrasound measured muscle thickness of the lower extremity: a brief review

Ultrasound is a potential method for assessing muscle size of the extremity and trunk. In a large muscle, however, a single image from portable ultrasound measures only muscle thickness (MT), not anatomical muscle cross-sectional area (CSA) or muscle volume (MV). Thus, it is important to know whether MT is related to anatomical CSA and MV in an individual muscle of the extremity and trunk. In this review, we summarize previously published articles in the lower extremity demonstrating the relationships between ultrasound MT and muscle CSA or MV as measured by magnetic resonance imaging and computed tomography scans. The relationship between MT and isometric and isokinetic joint performance is also reviewed. A linear relationship is observed between MT and muscle CSA or MV in the quadriceps, adductor, tibialis anterior, and triceps surae muscles. Intrarater correlation coefficients range from 0.90 to 0.99, except for one study. It would appear that anterior upper-thigh MT, mid-thigh MT and posterior thigh MT are the best predictors for evaluating adductor, quadriceps, and hamstrings muscle size, respectively. Despite a limited number of studies, anterior as well as posterior lower leg MT appear to reflect muscle CSA and MV of the lower leg muscles. Based on previous studies, ultrasound measured anterior thigh MT may be a valuable predictor of knee extension strength. Nevertheless, more studies are needed to clarify the relationship between lower extremity function and MT.

Quantifying skeletal muscle recovery in a rat injury model using ultrasound imaging

Monitoring skeletal muscle health during recovery or degeneration is of great interest both clinically and in research settings. This type of monitoring requires health measurements be taken at multiple time points. Contraction strength is a commonly used metric for quantifying muscle health, but it requires invasive in vitro or in situ procedures that may further damage the tissue. Ultrasound imaging can be used to visualize muscle damage, and semi-quantitative grading scales have been shown to be effective at characterizing abnormalities. Using an established functional testing procedure in a rat model as a baseline measurement of muscle strength, we show that ultrasound imaging combined with a semi-quantitative grading scale can be used to monitor recovery after contusion injury. Although additional work is needed to refine the imaging and grading procedures, ultrasound promises a fast and non-invasive alternative to functional testing for characterizing skeletal muscle health.

Effects of follicular versus luteal phase-based strength training in young women

Hormonal variations during the menstrual cycle (MC) may influence trainability of strength. We investigated the effects of a follicular phase-based strength training (FT) on muscle strength, muscle volume and microscopic parameters, comparing it to a luteal phase-based training (LT). Eumenorrheic women without oral contraception (OC) (N = 20, age: 25.9 ± 4.5 yr, height: 164.2 ± 5.5 cm, weight: 60.6 ± 7.8 kg) completed strength training on a leg press for three MC, and 9 of them participated in muscle biopsies. One leg had eight training sessions in the follicular phases (FP) and only two sessions in the luteal phases (LP) for follicular phase-based training (FT), while the other leg had eight training sessions in LP and only two sessions in FP for luteal phase-based training (LT). Estradiol (E2), progesterone (P4), total testosterone (T), free testosterone (free T) and DHEA-s were analysed once during FP (around day 11) and once during LP (around day 25). Maximum isometric force (Fmax), muscle diameter (Mdm), muscle fibre composition (No), fibre diameter (Fdm) and cell nuclei-to-fibre ratio (N/F) were analysed before and after the training intervention. T and free T were higher in FP compared to LP prior to the training intervention (P < 0.05). The increase in Fmax after FT was higher compared to LT (P <0.05). FT also showed a higher increase in Mdm than LT (P < 0.05). Moreover, we found significant increases in Fdm of fibre type ΙΙ and in N/F only after FT; however, there was no significant difference from LT. With regard to change in fibre composition, no differences were observed between FT and LT. FT showed a higher gain in muscle strength and muscle diameter than LT. As a result, we recommend that eumenorrheic females without OC should base the periodization of their strength training on their individual MC.

Ultrasound assessment of hamstring muscle size using posterior thigh muscle thickness

Several studies have investigated the relationship between ultrasound-measured muscle thickness (MT) and individual muscle cross-sectional area (CSA) and muscle volume (MV) in extremity and trunk muscles; however, the hamstring muscle has not been studied. The purpose of this study was to examine the relationship between posterior thigh MT by ultrasound and the muscle CSA and MV of the hamstring obtained by magnetic resonance imaging (MRI). Ten young women aged 20-31 had MT measured by ultrasound at three sites on the medial anterior (50% of thigh length; TL) and posterior (50% and 70% of TL) aspects of the thigh. On the same day, a series of continuous muscle CSA along the thigh was measured by MRI. In each slice, the anatomical CSA of the hamstring (biceps femoris, semitendinosus and semimembranosus) and quadriceps muscle was analysed, and the CSAs at 50% and 70% of TL and maximal CSA of the hamstring (CSAmax ) were determined. MV was calculated by multiplying CSA by slice thickness. A significant correlation was observed between posterior 50% MT and 50% hamstring CSA (r = 0·848, P = 0·002) and between posterior 70% MT and 70% hamstring CSA (r = 0·679, P = 0·031). Posterior 50% MT (r = 0·732, P = 0·016) and 50% MTxTL (r = 0·873, P = 0·001) were also correlated to hamstring MV. Anterior:posterior 50% thigh MT ratio was correlated to MV ratio of quadriceps and hamstring muscles (r = 0·803, P = 0·005). Our results suggest that posterior thigh MT reflects hamstring muscle CSA and MV. The anterior:posterior MT ratio may serve as a surrogate for MV ratio of quadriceps and hamstring.

Averaging improves strain images of the biceps brachii using quasi-static ultrasound elastography

OBJECTIVE

Quasi-static ultrasound elastography is a technique for measuring tissue deformation (strain) under externally applied loading and can be used to identify the presence of abnormalities. The objective of this study was to demonstrate the efficacy of averaging strain images from repeated compression cycles in mitigating user-induced error using quasi-static ultrasound elastography.

METHODS

Freehand compressions were performed with an ultrasound transducer on the biceps brachii of nine participants (five males and four females), as well as with a custom automated compression system. Sets of strain images from the freehand techniques were averaged to create single representative images and compared against strain images from the automated compressions using both qualitative and quantitative metrics.

RESULTS

Significant improvements in intra-operator repeatability and interoperator reproducibility can be achieved by averaging strain images from four to eight repeated compressions. The resulting strain images did not lose significant image data compared with strain images from single automated compressions.

CONCLUSION

Averaging is introduced as a feasible and appropriate technique to improve strain image quality without sacrificing important image data.

ADVANCES IN KNOWLEDGE

Simple averaging of multiple freehand elastography measures can achieve a similar degree of accuracy, repeatability and reproducibility as that of more awkward and expensive automated methods. The resulting elastograms can be used to obtain a more accurate and complete diagnosis without additional cost to the doctor or the patient.

Reliability of ultrasound for measurement of selected foot structures

BACKGROUND

Understanding the relationship between the lower leg muscles, foot structures and function is essential to explain how disease or injury may relate to changes in foot function and clinical pathology. The aim of this study was to investigate the inter-operator reliability of an ultrasound protocol to quantify features of: rear, mid and forefoot sections of the plantar fascia (PF); flexor hallucis brevis (FHB); flexor digitorum brevis (FDB); abductor hallucis (AbH); flexor digitorum longus (FDL); flexor hallucis longus (FHL); tibialis anterior (TA); and peroneus longus and brevis (PER).

METHODS

A sample of 6 females and 4 males (mean age 29.1 ± 7.2 years, mean BMI 25.5 ± 4.8) was recruited from a university student and staff population. Scans were obtained using a portable Venue 40 musculoskeletal ultrasound system (GE Healthcare UK) with a 5-13 MHz wideband linear array probe with a 12.7 mm × 47.1mm footprint by two operators in the same scanning session.

RESULTS

Intraclass Correlation Coefficients (ICC) values for muscle thickness (ICC range 0.90-0.97), plantar fascia thickness (ICC range 0.94-0.98) and cross sectional muscle measurements (ICC range 0.91-0.98) revealed excellent inter-operator reliability. The limits of agreement, relative to structure size, ranged from 9.0% to 17.5% for muscle thickness, 11.0-18.0% for plantar fascia, and 11.0-26.0% for cross sectional area measurements.

CONCLUSIONS

The ultrasound protocol implemented in this work has been shown to be reliable. It therefore offers the opportunity to quantify the structures concerned and better understand their contributions to foot function.

Ultrasound of tibialis anterior muscle and tendon: anatomy, technique of examination, normal and pathologic appearance

Lesions of the tibialis anterior muscle and tendon are not frequently reported in international literature although pathology is not rare. Pathology can be spontaneous, associated with arthropathy or more generalized conditions. Clinical assessment may not be sufficient for distinguishing conditions like tendinopathy, tears, bursitis, etc. Therefore, imaging studies are necessary to plan appropriate therapy. US has a number of advantages, including widespread availability, absence of contraindications and low cost. It can also be used for dynamic studies of the muscle during contraction and relaxation. This article reviews the anatomy of the tibialis anterior, normal variants, the technique used for standard US examination of this muscle and tendon, its normal appearance on US and the sonographic characteristics of the most common lesions that affect it including tips on US-guided injections used for treatment.

The utility of ultrasound in detecting anterior compartment thickness changes in chronic exertional compartment syndrome: a pilot study

OBJECTIVE

To test the hypothesis that patients with chronic exertional compartment syndrome (CECS) of the anterior leg compartment have an increased anterior compartment thickness (ACT) compared with control subjects after exertion using ultrasound.

DESIGN

Prospective comparison study.

SETTING

Diagnostic imaging department of a tertiary care hospital.

PATIENTS

Four patients with CECS and 9 control subjects.

INTERVENTIONS

Patients with CECS and control subjects ran on a treadmill for up to 10 minutes. Anterior compartment thickness (both groups) and anterior compartment pressure (CECS patients) were measured before exertion and at scheduled intervals after exertion.

MAIN OUTCOME MEASURES

Anterior compartment thickness, percentage change in ACT from rest, and compartment pressure.

RESULTS

Anterior compartment pressures were diagnostic of CECS using the modified Pedowitz criteria in patients with CECS. Mean percentage change in ACT from rest in patients with CECS versus control subjects at 0.5 minutes was 21.3% versus 6.32% [95% confidence interval (CI), 6.92-35.6 and 0.094-12.5, respectively; P = 0.011]; at 2.5 minutes, it was 24.6% versus 4.22% (95% CI, 10.7-38.5 and -1.85-10.3, respectively; P = 0.003); and at 4.5 minutes, it was 24.9% versus 5.08% (95% CI, 14.3-35.5 and -0.813-11.0, respectively; P = 0.003). Mean ACT in patients with CECS versus control subjects significantly increased after exertion (P = 0.003) at 0.5 minutes, 2.5 minutes, and 4.5 minutes.

CONCLUSIONS

Ultrasonography reveals a significant increase in ACT in patients with CECS of the anterior leg compartment. Further studies are warranted to validate these findings with the goal of developing anterior leg compartment CECS ultrasound diagnostic criteria and exploring the role of using ultrasound to diagnose CECS in other compartments.

Ultrasonographic evaluation of the muscle architecture in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multi-system chronic inflammatory disease with a broad spectrum of clinical and serological manifestations. Although clinical evidence of proximal skeletal muscle involvement is not rare in patients with SLE, there is no knowledge about the effects of SLE on the macroscopic structural parameters of the muscles. Therefore, in this study, we aimed to explore the muscle strength and structure of SLE patients using isokinetic testing and ultrasonographic imaging. Thirty-one SLE patients (5 men, 26 women) with a mean age of 38.61 ± 10.68 years and mean disease duration of 3.71 ± 3.23 years without any previous history of myositis and 31 age- and sex-matched healthy subjects were enrolled. Demographic and clinical characteristics of the patients were recorded. Ultrasonographic evaluations were performed with a 7- to 12-MHz linear probe from vastus lateralis and gastrocnemius muscles of the nondominant extremity. Measurements included muscle thickness, pennation angle, and fascicule length. Isokinetic nondominant knee muscle strength tests were performed at 60 and 180°/s. We found that muscle thickness, pennation angle, and fascicle length of vastus lateralis muscles were increased in patients with SLE in comparison to control subjects (p < 0.001, p = 0.007, and p = 0.217, respectively). On the other hand, the measurements pertaining to the gastrocnemius muscles were found to be similar between the two groups. We observed that all isokinetic knee muscle strength values were decreased in SLE patients, and knee strength values were found to be negatively correlated with age and positively correlated with height (all p < 0.01). We found that the structural and strength changes were seen in the proximal muscles of SLE patients. Pathophysiology and clinical relevance of these changes need to be further investigated.

Reliability of ultrasound to measure morphology of the toe flexor muscles

Background

Measuring the strength of individual foot muscles is very challenging; however, measuring muscle morphology has been shown to be associated with strength. A reliable method of assessing foot muscle atrophy and hypertrophy would therefore be beneficial to researchers and clinicians. Thus, the aim of this study was to evaluate the test-retest intra-observer reliability of ultrasound to measure the morphology of the primary toe flexor muscles.

Method

The abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, quadratus plantae and abductor digiti minimi muscles in the foot, and the flexor digitorum longus and flexor hallucis longus muscles in the shank were assessed in five males and five females (mean age = 32.1 ± 10.1 years). Muscles were imaged using a GE Venue 40 ultrasound (6-9 or 7.6-10.7 MHz transducer) in a random order, and on two occasions 1-6 days apart. Muscle thickness and cross-sectional area were measured using Image J software with the assessor blinded to muscle and day of scan. Intraclass correlation coefficients (ICC) and limits of agreement were calculated to assess day-to-day repeatability of the measurements.

Results

The method was found to have good reliability (ICC = 0.89-0.99) with limits of agreement between 8-28% of the relative muscle size.

Conclusion

The protocol described in this paper showed that ultrasound is a reliable method to measure morphology of the toe flexor muscles. The portability and advantages of ultrasound make it a useful tool for clinical and research settings.

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.

Ultrasound measurement of the size of the anterior tibial muscle group: the effect of exercise and leg dominance

Background

Knowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for injured athletes. There is a high incidence of ankle and anterior tibial symptoms in football players, however little is known about the effect of limb dominance on the anterior tibial muscle group (ATMG). The purpose of this study was to assess the effect of limb dominance and sports-specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and to compare results from transverse and longitudinal scans.

Methods

Bilateral ultrasound scans were taken to assess the ATMG size in 10 Gaelic footballers and 10 sedentary controls (age range 18-25 yrs), using a previously published protocol. Both transverse and longitudinal images were taken. Muscle thickness measurements were carried out blind to group and side of dominance, using the Image-J programme.

Results

Muscle thickness on the dominant leg was significantly greater than the non-dominant leg in the footballers with a mean difference of 7.3%, while there was no significant dominance effect in the controls (p < 0.05). There was no significant difference between the measurements from transverse or longitudinal scans.

Conclusions

A significant dominance effect exists in ATMG size in this group of Gaelic footballers, likely attributable to the kicking action involved in the sport. This should be taken into account when rehabilitating footballers with anterior tibial pathology. Ultrasound is a reliable tool to measure ATMG thickness, and measurement may be taken in transverse or longitudinal section.

The association of nutritional status and gender with cross-sectional area of the multifidus muscle in establishing normative data

Despite recognized evidence for the importance of the multifidus muscle in stabilizing the lumbar spine, identifying subjects at risk for injury and subsequent loss of intrinsic spinal stabilization remains difficult. Previous research has failed to associate multifidus muscle size and height, weight, or body mass index (BMI). The purpose of this study was to begin to establish normative data for the multifidus muscle cross-sectional area (CSA) at the L5 level and to identify factors associated with size. Twenty-five participants (17 female), with a mean age of 32.5 (SD 11.6) years without history of LBP were considered for inclusion. Participants' height and weight were recorded and BMI calculated. Ultrasound imaging was used to obtain a CSA in cm(2) of the subjects' multifidus muscles at the L5 level bilaterally; testing was done by two trained testers. Prior to testing, intra- and inter-tester reliability were determined. Percent body fat was determined using a three-site skinfold caliper measurement, also using two trained testers. Mean BMI was 24.18 and mean body fat (%) was 22.88 for all participants. As expected, age and BMI were moderately correlated. Left and right multifidus muscle CSA were highly correlated (r = 0.92, p < 0.001). The mixed model ANOVA indicated a significant main effect for gender as males exhibited larger CSA than females. Participants without history of low back pain present with symmetrical multifidus muscle CSA at the L5 level. Clear gender differences in CSA show that males tend to have larger multifidus muscles at the L5 level, indicating a need to establish gender-specific norms for clinicians examining the L5 multifidus muscle.

Validity of real-time ultrasound imaging to measure anterior hip muscle size: a comparison with magnetic resonance imaging

STUDY DESIGN

Clinical measurement, criterion standard.

OBJECTIVES

To investigate the validity of real-time ultrasound imaging (USI) to measure individual anterior hip muscle cross-sectional area.

BACKGROUND

The hip flexor muscles are important for hip joint function and could be affected by joint pathology or injury. Objectively documenting individual anterior hip muscle size can be useful in identifying muscle size asymmetry and monitoring treatment efficacy for patients with hip problems. USI offers a novel method of measuring individual muscle size in the clinic, but its validity in measuring the anterior hip muscles has not been investigated.

METHODS

Nine healthy participants (5 males, 4 females) underwent imaging of their iliopsoas, sartorius, and rectus femoris muscles with USI and magnetic resonance imaging. Bilateral muscle cross-sectional areas were measured on images from both modalities.

RESULTS

There was no significant difference (P>.05) in mean cross-sectional area measurements from USI and magnetic resonance imaging for each muscle. Agreement between measurements was high for the iliopsoas (left: intraclass correlation coefficient [ICC3,1] = 0.86; 95% confidence interval [CI]: 0.51, 0.97; right: ICC3,1 = 0.88; 95% CI: 0.57, 0.97), sartorius (left: ICC3,1 = 0.82; 95% CI: 0.41, 0.96; right: ICC3,1 = 0.81; 95% CI: 0.39, 0.95), and rectus femoris (left: ICC3,1 = 0.85; 95% CI: 0.49, 0.96; right: ICC3,1 = 0.89; 95% CI: 0.61, 0.97). Reliability of measuring each muscle with USI was high between 2 trials (ICCs3,1 = 0.84 to 0.94).

CONCLUSION

USI is a valid measure of iliopsoas, sartorius, and rectus femoris muscle size in healthy people, as long as a strict measurement protocol is followed.

Application of rehabilitative ultrasound in the assessment of low back pain: a literature review

Low back pain (LBP) is one of the most common work-related conditions affecting all populations both in industrialized and non-industrialized countries, with reported high prevalence and incidence rates and huge direct and indirect costs. Among various suggested causes of LBP, dysfunction of back muscles, particularly lumbar multifidus and transverse abdominis, has been the subject of considerable research during last decades. Of the available imaging techniques, ultrasound (US) imaging technique is increasingly used to assess muscle dimensions and function as a valid, reliable and non-invasive approach. The purpose of the present study was to review the previously published studies (1990-2009) concerning the merit of US imaging of lumbar and abdominal muscles with particular attention to its clinical application in patients with LBP. Studies showed wide variation in terms of methodology, sample size, procedure, definition of LBP, heterogeneous sample, method of analyzing US imaging, US imaging parameters, etc. However, a convincing body of evidence was identified that supports US imaging as a reliable and valid tool both to differentiate patients with LBP from normal subjects and to monitor the effect of rehabilitation programs.

Human skeletal muscle size and architecture: Variability and interdependence

Seven hundred and eleven women and men (aged 3-94 years, including normal individuals and highly trained bodybuilders) were tested for the thickness and pennation angles of their triceps brachii (TB), vastus lateralis (VL), and gastrocnemius medialis (GM) muscles. The variations of muscle thickness and pennation angles were largest in TB (6-66 mm and 5-55 degrees), followed by VL (8-45 mm and 7-33 degrees) and GM (11-36 mm and 12-33 degrees), and women showed smaller variations than men. These results suggest the existence of muscle- and gender-specificity in the variability of muscle dimensions. Significant positive correlations were observed between muscle thickness and pennation angles (r = 0.81, 0.61, and 0.56, for TB, VL, and GM, respectively), indicating that the size-dependence of the pennation angle is a general feature of pennate muscles.

Venous Obstruction in Healthy Limbs: A Model for Chronic Compartment Syndrome?

PURPOSE

Chronic exertional compartment syndrome (CECS) in the anterior tibial (AT) compartment is generally believed to be the result of reduced venous blood flow caused by restrictive compartments and increased intramuscular pressures. If this is so, then restricting venous flow in the muscles of healthy subjects during exercise should mimic CECS.

METHODS

This hypothesis was tested in 10 control subjects (aged 19-41 yr, five males) with and without external venous occlusion induced by a sphygmomanometer cuff fitted just below the knee and inflated to 80 mm Hg. Twenty CECS patients (20-39 yr, 16 males) were studied without external occlusion. Subjects performed intermittent, isometric maximal voluntary contractions (MVC) of the AT for 20 min (1.6-s contractions, 0.5 duty cycle). MVC, tetanic force (2 s at 50 Hz), muscle thickness (ultrasound imaging), and pain were measured during exercise and 10 min of recovery.

RESULTS

Venous occlusion in the controls induced greater pain, fatigue, and increase in muscle thickness (P < 0.01). Initially the patients fatigued more slowly than the occluded controls, but at the end of exercise, the fatigue and pain were similar in these two groups. The controls showed a greater increase in muscle size (P = 0.01). Recovery was similar in all three groups, although the size of the patients' muscles recovered rather more slowly.

CONCLUSION

External venous occlusion of the AT muscles in control subjects induces changes very similar to those of CECS patients, although the different time courses indicate that different processes are involved. The AT compartment of CECS patients is capable of distension.

Development of predictive equations for body density of sumo wrestlers using B-mode ultrasound for the determination of subcutaneous fat thickness

OBJECTIVE

To develop an equation for predicting the body density of sumo wrestlers.

METHODS

The following were measured: subcutaneous fat thickness measured at nine sites using B-mode ultrasound equipment; circumference at seven sites; hand to leg bioelectrical impedance. The subjects consisted of 24 college sumo wrestlers (mean age 19.7 years, mean body weight 111.2 kg) and 24 matched obese controls (mean age 19.1 years and mean body weight 111.2 kg). In addition, body density was measured by the underwater weighing method, and the percentage of fat was calculated from the measured body density.

RESULTS

Linear regression analysis was used to estimate the relation between body density and other variables, and a predictive equation for the body density was derived: y = 1.088-0.00036 x (fat thickness at nine sites) (r(2) = 0.90) for the sumo wrestler group and y = 1.083-0.00033 x (fat thickness at nine sites) (r(2) = 0.91) for the control group. A multiple regression analysis was performed using the body density as the objective variable, and other measured items as the explanatory variables. This was used to derive a predictive equation: y = 1.121-0.00038 x (fat thickness of abdomen)-0.00043 x (circumference of hips)-0.00142 x (fat thickness of triceps) (r(2) = 0.94) for the sumo wrestler group, and y = 1.076-0.00070 x (fat thickness of abdomen)-0.00140 x (fat thickness of tibialis) (r(2) = 0.91) for the control group. The difference between the two equations was due to the difference in body fat distribution. Neither of these predictive equations is applicable to non-overweight non-athletes.

CONCLUSION

This is the first predictive equation developed for the body density of sumo wrestlers.

Muscle ultrasound analysis: normal values and differentiation between myopathies and neuropathies

In this study, 145 healthy adults (20 to 94 years old, 69 women) were examined using ultrasound (US) imaging to obtain reference values of muscle parameters that were previously not available. We measured biceps and quadriceps sizes and subcutaneous fat thickness. To quantify muscle aspect, we defined and calculated the muscle aspect parameters muscle density, inhomogeneity and white-area index by digital image analysis. All muscle aspect parameters were found to increase with age, which may be due to age-related muscle replacement by fatty tissue and collagen. Other age-, weight- and gender-dependencies are also discussed. The complete set of muscle parameters was used to differentiate between typical myopathies and neuropathies in a group of 32 patients (24 to 79 years old, 18 women). We were successful in almost completely separating the two types of disorders based on abnormality of muscle aspect parameters alone. These preliminary results show that this set of normal muscle parameters can be used to help diagnose neuromuscular disorders. It will also facilitate follow-up in disease progression and therapy.

Chronic exertional compartment syndrome: muscle changes with isometric exercise

Chronic exertional compartment syndrome (CECS) is a well-documented cause of lower leg pain in active individuals. The pathophysiology is unclear, although it is generally believed to be associated with increased intramuscular pressure, but there is very little information about muscle function in relation to the onset of pain.

PURPOSE

To investigate strength, fatigue, and recovery of the anterior tibial muscles in CECS patients and healthy subjects during an isometric exercise protocol.

METHODS

Twenty patients and 22 control subjects (mean age 27.6 yr and 33.0 yr, respectively) performed a 20-min isometric exercise protocol consisting of intermittent maximal voluntary contractions (MVC). Central fatigue was evaluated by comparing changes in electrically stimulated (2 s at 50 Hz) and voluntary contraction force before and during the exercise, and then throughout 10 min of recovery. Muscle size was measured by ultrasonography. Pain and cardiovascular parameters were also examined.

RESULTS

The absolute MVC forces were similar, but MVC:body mass of the patients was lower (P < 0.05) as was the ratio of MVC to muscle cross-sectional area (P < 0.01). The extent of central and peripheral fatigue was similar in the two groups. The patients reported significantly higher levels of pain during exercise (P < 0.05 at 4 min) and after the first minute of recovery (P < 0.001). An 8% increase in muscle size after exercise was observed for both groups. There were no differences in the cardiovascular responses of the two groups.

CONCLUSIONS

CECS patients were somewhat weaker than normal but fatigued at a similar rate during isometric exercise. Patients reported higher pain than controls despite comparable changes in muscle size, suggesting that abnormally tight fascia are not the main cause of CECS symptoms.

Comparison of muscle sizes and moment arms of two rotator cuff muscles measured by ultrasonography and magnetic resonance imaging

OBJECTIVE

The purpose was to investigate ultrasound (US) and anthropometry (AN) as valid alternatives to magnetic resonance imaging (MRI) regarding muscle size characteristics of two rotator cuff muscles.

METHODS

Eight healthy females (age 27-54 yrs.) went through MRI and US scannings and AN measurements, where muscle thickness, cross-section area (CSA), moment arm, muscle length and width were measured on supraspinatus and infraspinatus muscle.

RESULTS

The agreement between the methods was very satisfactory for CSA, and satisfactory for muscle thickness, moment arm, muscle length and width, with a mean difference below 2 mm in thickness and below 5 mm in muscle length and width. Volume could be estimated satisfactory in supraspinatus muscle, but not in infraspinatus muscle, where volume had to be calculated from thickness, length and width. As a significant relation was found in the MRI measurements between thickness and CSA, thickness measurements may replace CSA in inaccessible muscles.

CONCLUSIONS

US was a valid method in measuring CSA, muscle thickness and moment arm. Combined with anthropometric measures of muscle length and width, volume can be calculated, which is important when defining the physiological cross-sectional area and muscle function. Further development and validation of the method is needed, however.

Neck muscle ultrasonography of male weight-lifters, wrestlers and controls

The purpose of this cross-sectional study was to evaluate the effect of different sport training regimens on the size of the neck semispinalis capitis muscle (SECM). The cross-sectional area (CSA) and the linear dimensions of the SECM were measured bilaterally by real-time ultrasonography. Ten young Finnish elite level weight-lifters, 8 freestyle wrestlers and 10 controls (all male) participated in the study. Muscle CSA was significantly larger in wrestlers than in weight-lifters or controls (P < 0.001). There was no significant difference in size between the right and left SECM in any of the subject groups, but the variation between sides (smaller vs. larger) was significantly higher in wrestlers than weight-lifters (P < 0.05). CSA correlated with the multiplied linear dimensions (r = 0.80, P < 0.000). Neck muscle: ultrasonography appeared to be a useful method in evaluating the differences between two groups of athletes.

Reliability of assessment tools in rehabilitation: an illustration of appropriate statistical analyses

OBJECTIVE

To provide a practical guide to appropriate statistical analysis of a reliability study using real-time ultrasound for measuring muscle size as an example.

DESIGN

Inter-rater and intra-rater (between-scans and between-days) reliability.

SUBJECTS

Ten normal subjects (five male) aged 22-58 years.

METHOD

The cross-sectional area (CSA) of the anterior tibial muscle group was measured using real-time ultrasonography.

MAIN OUTCOME MEASURES

Intraclass correlation coefficients (ICCs) and the 95% confidence interval (CI) for the ICCs, and Bland and Altman method for assessing agreement, which includes calculation of the mean difference between measures (d), the 95% CI for d, the standard deviation of the differences (SDdiff), the 95% limits of agreement and a reliability coefficient.

RESULTS

Inter-rater reliability was high, ICC (3,1) was 0.92 with a 95% CI of 0.72 --> 0.98. There was reasonable agreement between measures on the Bland and Altman test, as d was -0.63 cm2, the 95% CI for d was -1.4 --> 0.14 cm2, the SDdiff was 1.08 cm2, the 95% limits of agreement -2.73 --> 1.53 cm2 and the reliability coefficient was 2.4. Between-scans repeatability was high, ICCs (1,1) were 0.94 and 0.93 with 95% CIs of 0.8 --> 0.99 and 0.75 --> 0.98, for days 1 and 2 respectively. Measures showed good agreement on the Bland and Altman test: d for day 1 was 0.15 cm2 and for day 2 it was -0.32 cm2, the 95% CIs for d were -0.51 --> 0.81 cm2 for day 1 and -0.98 --> 0.34 cm2 for day 2; SDdiff was 0.93 cm2 for both days, the 95% imits of agreement were -1.71 --> 2.01 cm2 for day 1 and -2.18 --> 1.54 cm2 for day 2; the reliability coefficient was 1.80 for day 1 and 1.88 for day 2. The between-days ICC (1,2) was 0.92 and the 95% CI 0.69 --> 0.98. The d was -0.98 cm2, the SDdiff was 1.25 cm2 with 95% limits of agreement of -3.48 --> 1.52 cm2 and the reliability coefficient 2.8. The 95% CI for d (-1.88 --> -0.08 cm2) and the distribution graph showed a bias towards a larger measurement on day 2.

CONCLUSIONS

The ICC and Bland and Altman tests are appropriate for analysis of reliability studies of similar design to that described, but neither test alone provides sufficient information and it is recommended that both are used.