Can ultrasound measurements of muscle thickness be used to measure the size of individual quadriceps muscles in people with patellofemoral pain?

Intermittent blood flow restriction with low-load resistance training for older adults with knee osteoarthritis: a randomized, controlled, non-inferiority trial protocol

BACKGROUND

Knee osteoarthritis (KOA) is a chronic musculoskeletal disorder characterized by pain and functional impairment. Blood flow restriction (BFR) with low-load resistance training (LLRT) demonstrates a similar improvement in clinical outcomes to high-load resistance training (HLRT) in treating KOA. It has not been established whether intermittent blood flow restriction (iBFR) with LLRT can lead to clinical outcomes that are comparable to those produced by continuous blood flow restriction (cBFR) with LLRT and HLRT. The aim of the proposed study is to evaluate the efficacy of iBFR with LLRT on pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence in KOA patients.

METHODS

This is a three-arm, non-inferiority, randomized controlled trial utilizing blinded assessors. Two hundred thirteen participants will be randomly allocated to one of the following three groups: iBFR group-receiving 4 months of LLRT with iBFR, twice weekly (n = 71); cBFR group-receiving 4 months of LLRT with cBFR, twice weekly (n = 71); or HLRT group-receiving 4 months of HLRT without BFR, twice weekly (n = 71). The primary outcome is pain. The secondary outcomes include the WOMAC, muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence. Pain and WOMAC will be measured at the baseline and 4 and 12 months after randomizations. Muscle strength, muscle mass, and physical function will be measured at the baseline and 4 months after randomizations. The perceptions of discomfort and effort will be measured during the first and final sessions.

DISCUSSION

BFR with LLRT has a similar improvement in clinical outcomes as HLRT. However, cBFR may cause elevated ratings of perceived exertion and local discomfort, compromising patient tolerability and treatment adherence. If iBFR with LLRT could produce improvement in clinical outcomes analogous to those of HLRT and iBFR with LLRT, it could be considered an alternative approach for treating patients with KOA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300072820. Registered on June 26, 2023.

Sports activity level after ACL reconstruction is predicted by vastus medialis or vastus medialis obliquus thickness, single leg triple hop distance or 6-m timed hop, and quality of life score

PURPOSE

Recovery after anterior cruciate ligament reconstruction (ACLR) may take > 2 years, and younger athletes have higher re-injury risk. The purpose of this prospective longitudinal study was to determine how the early to mid-term Tegner Activity Level Scale (TALS) scores of athletically active males ≥ 2 years post-ACLR follow-up was predicted by bilateral isokinetic knee extensor and flexor torque, quadriceps femoris thickness, single leg hop test performance, and self-reported knee function (Knee Injury and Osteoarthritis Outcome Score (KOOS); International Knee Documentation Committee (IKDC) Subjective Assessment score).

METHODS

After ACLR with a hamstring tendon autograft and safely returning to sports at least twice weekly, 23 men (18.4 ± 3.5 years of age) were evaluated at final follow-up (mean = 4.5, range = 2-7 years). Exploratory forward stepwise multiple regression was used to determine the relationship between independent surgical and non-surgical lower limb variables peak concentric isokinetic knee extensor-flexor torque at 60°/sec and 180°/sec, quadriceps femoris muscle thickness, single leg hop test profile results, KOOS subscale scores, IKDC Subjective Assessment scores, and time post-ACLR on TALS scores at final follow-up.

RESULTS

Subject TALS scores were predicted by KOOS quality of life subscale score, surgical limb vastus medialis obliquus (VMO) thickness, and surgical limb single leg triple hop for distance (SLTHD) performance. Subject TALS scores were also predicted by KOOS quality of life subscale score, non-surgical limb vastus medialis (VM) thickness, and non-surgical limb 6 m single leg timed hop (6MSLTH) performance.

CONCLUSION

TALS scores were influenced differently by surgical and non-surgical lower extremity factors. At ≥ 2 years post-ACLR, ultrasound VM and VMO thickness measurements, single leg hop tests that challenge knee extensor function, and self-reported quality of life measurements predicted sports activity levels. The SLTHD test may be better than the 6MSLTH for predicting long-term surgical limb function.

Influence of individual quadriceps and hamstrings muscle architecture and quality on knee adduction and flexion moment in gait

The purpose of this study was to investigate the relationship between muscular parameters of quadriceps/hamstrings and knee joint kinetics in gait. Muscle architecture (thickness, pennation angle, and fascicle length), and quality (echo intensity) of individual quadriceps and hamstrings of 30 healthy participants (16 males and 14 females) was measured using ultrasound. Peak knee flexion moment (KFM), KFM impulse, peak knee adduction moment (KAM), and KAM impulse during walking were obtained at preferred speed. Pearson's correlation coefficient and multiple regression analyses were performed at significance level of 0.05, and Cohen's f2 values were calculated to examine the effect sizes of multiple regression. The hamstring-to-quadriceps muscle thickness ratio (r = 0.373) and semitendinosus echo intensity (r =  - 0.371) were predictors of first peak KFM (R2 = 0.294, P = 0.009, f2 = 0.42), whereas only vastus medialis (VM) echo intensity was a significant predictor of second peak KFM (r = 0.517, R2 = 0.267, P = 0.003, f2 = 0.36). Only the VM thickness was the predictor of first (r = 0.504, R2 = 0.254, P = 0.005, f2 = 0.34) and second peak KAM (r = 0.581, R2 = 0.337, P = 0.001, f2 = 0.51), and KAM impulse (r = 0.693, R2 = 0.480, P < 0.001, f2 = 0.92). In conclusion, the greater hamstring-to-quadriceps muscle thickness ratio and the muscle architecture and quality of medial quadriceps/hamstring play an important role in KFM and KAM, and may have implications in knee osteoarthritis.

The effects of regional quadriceps architecture on angle-specific rapid force expression

Evaluating anatomical contributions to performance can increase understanding of muscle mechanics and guide physical preparation. While the impact of anatomy on muscular performance is well studied, the effects of regional quadriceps architecture on rapid torque or force expression are less clear. Regional (proximal, middle, and distal) quadriceps (vastus lateralis, rectus femoris, and vastus intermedius) thickness (MT), pennation angle (PA), and fascicle length (FL) of 24 males (48 limbs) were assessed via ultrasonography. Participants performed maximal isometric knee extensions at 40°, 70°, and 100° of knee flexion to evaluate rate of force development from 0 to 200 ms (RFD0-200). Measurements were repeated on three occasions with the greatest RFD0-200 and mean muscle architecture measures used for analysis. Linear regression models predicting angle-specific RFD0-200 from regional anatomy provided adjusted correlations (√adjR2) with bootstrapped compatibility limits. Mid-rectus femoris MT (√adjR2 = 0.41-0.51) and proximal vastus lateralis FL (√adjR2 = 0.42-0.48) were the best single predictors of RFD0-200, and the only measures to reach precision with 99% compatibility limits. Small simple correlations were found across all regions and joint angles between RFD0-200 and vastus lateralis MT (√adjR2 = 0.28 ± 0.13; mean ± SD), vastus lateralis FL (√adjR2 = 0.33 ± 0.10), rectus femoris MT (√adjR2 = 0.38 ± 0.10), and lateral vastus intermedius MT (√adjR2 = 0.24 ± 0.10). Between-correlation comparisons are reported within the article. Researchers should measure mid-region rectus femoris MT and vastus lateralis FL to efficiently and robustly evaluate potential anatomical contributions to rapid knee extension force changes, with distal and proximal measurements providing little additional value. However, correlations were generally small to moderate, suggesting that neurological factors may be critical in rapid force expression.

Comparing the effect of intermittent blood flow restriction training and high-load resistance training in patients with patellofemoral pain: study protocol for a randomised trial

BACKGROUND

Patellofemoral pain (PFP) syndrome is a common knee joint functional disorder. Blood flow restriction (BFR) training has shown promise in improving PFP; however, the effectiveness of intermittent BFR (iBFR) training remains uncertain. This study aims to compare the rehabilitative effects of iBFR combined with low-load resistance training and high-load resistance training in PFP patients and to assess the effectiveness of iBFR combined with low-load resistance training for improving PFP.

METHODS AND ANALYSIS

This randomised, patient-assessor blinded, controlled trial will include 42 eligible PFP patients randomly allocated to an intervention group (iBFR combined with low-load resistance training) or a control group (high-load resistance training) in a 1:1 ratio. Participants will receive interventions three times per week for 8 weeks and will be followed up for 24 weeks. The primary outcome measure is pain, and the secondary outcomes include self-reported function, quality of life, muscle strength and muscle thickness. Assessments will be conducted at baseline, 8 weeks and 24 weeks during follow-up. Intention-to-treat analysis will be performed.Collectively, we expect that the findings of this randomised clinical trial will contribute to understanding the potential benefits of iBFR training and provide insightful guidance for developing more effective treatment strategies for patients with PFP.

ETHICS AND DISSEMINATION

This study was approved by the Sports Science Experiment Ethics Committee of Beijing Sport University (2022274H). Written informed consent will be obtained from all participants. Trial results will be disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2300068281).

Association between quadriceps muscle thickness and knee function in anterior cruciate ligament reconstructed athletes: a cross-sectional study

OBJECTIVE

This study aimed to investigate the association between vastus medialis obliquus (VMO), rectus femoris (RF), and vastus lateralis (VL) muscle thickness and quadriceps isokinetic strength, single-leg hop performance, and self-reported knee function in male athletes who had undergone anterior cruciate ligament reconstruction (ACLR).

METHODS

Forty-two male athletes [mean ± standard deviation, age: 21.4 ± 3.4 years], who had undergone ACLR and had cleared to return to activity, were included in this study. Real-time ultrasound images of VMO, RF, and VL thicknesses were obtained from both reconstructed and contralateral limbs. Concentric quadriceps peak torque at 60°/s and 180°/s, single-leg hop for Distance (SLHD), and self-reported knee function scores were also assessed. Linear regression analysis and student t tests were used for statistical analysis.

RESULTS

In reconstructed limb, greater VMO, RF, and VL thicknesses were associated with greater quadriceps peak torque at 60°/s (p = .008, r2 = 0.46) and at 180°/s (p = .006, r2 = 0.47). Greater quadriceps thickness was related to greater SLHD score in reconstructed limb (p = .002, r2 = 0.21). Self-reported knee function scores were not related to quadriceps thickness. VMO, RF, and VL thicknesses were smaller in reconstructed limb compared to contralateral limb (p < .001, p = .01, and p = .002, respectively).

CONCLUSION

Quadriceps thickness by using ultrasound was associated with concentric quadriceps strength and single-leg hop distance in individuals who had undergone ACLR. However, quadriceps thickness was not related to self-reported knee function. The ultrasonography may be included in the evaluation of the knee function after ACLR, and it may be a useful and easy method in the follow-up of the quadriceps strength recovery following ACLR.

Sitting vs. supine ultrasound measurements of the vastus medialis: correlations with MRI measurements and age considerations

BACKGROUND

Muscle thickness (MT) and echo intensity (EI) measurements are ultrasound alternatives to magnetic resonance imaging (MRI) for evaluating muscle quantity and quality. The vastus medialis (VM) is a clinically important muscle, and assessment methods that most accurately reflect its quantity and quality are required. This study aimed to examine the correlation between MT and EI measured in the supine and sitting postures with corresponding MRI-measured muscle quantity and quality indices.

METHODS

In total, 134 adults (91 older and 43 young) participated in this study. Ultrasound images of the VM were acquired in the supine and sitting postures, and MT and EI were measured. The cross-sectional area (CSA), muscle volume (MV), and intramuscular adipose tissue (intraMAT) of the VM were evaluated from MRI images using T1-weighted and Dixon methods. Pearson's coefficients were used to quantify the correlation strength amongst pairs of dependent variables. Meng's test was used to test for correlation coefficient differences between the two measurement postures (supine and sitting).

RESULTS

The correlation coefficients amongst MT, CSA, and MV were significantly higher in the sitting posture than in the supine posture. EI measured in the supine and sitting postures correlated significantly with intraMAT, and in young individuals, these correlation coefficients were significantly higher in the sitting posture than in the supine posture.

CONCLUSIONS

These findings suggest that assessment of VM muscle quantity in the sitting posture is superior for young and older individuals, and assessment of VM muscle quality in the sitting posture is most effective in younger individuals.

Association Between the Medial-Lateral Quadriceps and Hamstring Muscle Thickness and the Knee Kinematics and Kinetics During Single-Leg Landing

BACKGROUND

Muscle thickness can influence the joint kinematics and/or kinetics during dynamic activities. The relationship between the muscle thickness of individual quadriceps and hamstrings or medial-to-lateral thigh muscle thickness ratio and the knee kinematics/kinetics with respect to anterior cruciate ligament (ACL) injury risk remains unclear.

HYPOTHESIS

Higher medial-to-lateral thigh muscle thickness ratio would be associated with lower knee valgus angle/moment and lower tibial internal rotation angle/moment during single-leg landing.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 4.

METHODS

Muscle thickness of the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and semitendinosus (ST) of 30 healthy participants (16 males and 14 females) were measured using ultrasound. Knee joint kinematics and kinetics during single-leg landing were obtained. Stepwise multiple regression analysis, a follow-up Fisher's r to z test to examine the sex as a moderator, and independent t tests to evaluate sex difference were performed.

RESULTS

Both knee valgus moment (R2 = 0.466, P < 0.001) and tibial external rotation moment (R2 = 0.330, P < 0.001) at peak anterior tibial shear force during single-leg landing were negatively correlated with medial-to-lateral (ie, (VM+ST):(VL+BF)) thickness ratio regardless of sex, whereas medial-to-lateral thigh muscle thickness ratio was not correlated with knee valgus and tibial external rotation angles. Male participants exhibited higher (VM+ST):(VL+BF) thickness ratio than female participants (P = 0.005), and lower knee valgus moment (P = 0.04) and tibial external rotation moment (P = 0.05), as well.

CONCLUSION

The knee joint moments in frontal and transverse planes during single-leg landing were associated with the medial-to-lateral thigh muscle thickness ratio; thus, the medial-lateral thigh muscle thickness could be a potential contributor to frontal and transverse plane knee joint loading during dynamic movement.

CLINICAL RELEVANCE

Strength training that aims to selectively strengthen the medial/lateral thigh muscles might be considered in a new ACL injury prevention training program to alter the biomechanical parameters associated with ACL injuries.

Skeletal Muscle Measurements in Pediatric Hematology and Oncology: Essential Components to a Comprehensive Assessment

Children with hematologic and oncologic health conditions are at risk of impaired skeletal muscle strength, size, and neuromuscular activation that may limit gross motor performance. A comprehensive assessment of neuromuscular function of these children is essential to identify the trajectory of changes in skeletal muscle and to prescribe therapeutic exercise and monitor its impact. Therefore, this review aims to (a) define fundamental properties of skeletal muscle; (b) highlight methods to quantify muscle strength, size, and neuromuscular activation; (c) describe mechanisms that contribute to muscle strength and gross motor performance in children; (d) recommend clinical assessment measures; and (e) illustrate comprehensive muscle assessment in children using examples of sickle cell disease and musculoskeletal sarcoma.

Reliability and Validity of an Ultrasound-Based Protocol for Measurement of Quadriceps Muscle Thickness in Children

Introduction and aims: Accurate determination of skeletal muscle size is of great importance in multiple settings including resistance exercise, aging, disease, and disuse. Ultrasound (US) measurement of muscle thickness (MT) is a method of relatively high availability and low cost. The present study aims to evaluate a multisite ultrasonographic protocol for measurement of MT with respect to reproducibility and correlation to gold-standard measurements of muscle volume (MV) with magnetic resonance imaging (MRI) in children.

Material and methods: 15 children completed the study (11 ± 1 year, 41 ± 8 kg, 137 ± 35 cm). Following 20 min supine rest, two investigators performed US MT measurements of all four heads of the m. quadriceps femoris, at pre-determined sites. Subsequently, MRI scanning was performed and MV was estimated by manual contouring of individual muscle heads.

Results: Ultrasound measurement of MT had an intra-rater reliability of ICC = 0.985–0.998 (CI 95% = 0.972–0.998) and inter-rater reliability of ICC = 0.868–0.964 (CI 95% = 0.637–0.983). The US examinations took less than 15 min, per investigator. Muscle thickness of all individual quadriceps muscles correlated significantly with their corresponding MV as measured by MRI (overall r = 0.789, p < 0.001).

Conclusion: The results of this study indicate that US measurement of MT using a multisite protocol is a competitive alternative to MRI scanning, especially with respect to availability and time consumption. Therefore, US MT could allow for wider clinical and scientific implementation.

Effect of low-load resistance training with different degrees of blood flow restriction in patients with knee osteoarthritis: study protocol for a randomized trial

BACKGROUND

Knee osteoarthritis (KOA) is a common degenerative disease that causes pain, functional impairment, and reduced quality of life. Resistance training is considered as an effective approach to reduce the risk of muscle weakness in patients with KOA. Blood flow restriction (BFR) with low-load resistance training has better clinical outcomes than low-load resistance training alone. However, the degree of BFR which works more effectively with low-load resistance training has not been determined. The purpose of this study is to evaluate the effectiveness of different degrees of BFR with low-load resistance training in patients with KOA on pain, self-reported function, physical function performance, muscle strength, muscle thickness, and quality of life.

METHODS

This is a study protocol for a randomized, controlled trial with blinded participants. One hundred individuals will be indiscriminately assigned into the following groups: two training groups with a BFR at 40% and 80% limb occlusion pressure (LOP), a training group without BFR, and a health education group. The three intervention groups will perform strength training for the quadriceps muscles twice a week for 12 weeks, while the health education group will attend sessions once a week for 12 weeks. The primary outcome is pain. The secondary outcomes include self-reported function, physical function performance, muscle strength of the knee extensors, muscle mass of the quadriceps, quality of life, and adverse events. Intention-to-treat analysis will be conducted for individuals who withdraw during the trial.

DISCUSSION

Previous studies have shown that BFR with low-load resistance training is more effective than low-load resistance training alone; however, a high degree of BFR may cause discomfort during training. If a 40% LOP for BFR could produce similar clinical outcomes as an 80% LOP for BFR, resistance training with a low degree of BFR can be chosen for patients with KOA who are unbearable for a high degree of BFR.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000037859 ( http://www.chictr.org.cn/edit.aspx?pid=59956&htm=4 ). Registered on 2 September 2020.

Foot and Lower Limb Clinical and Structural Changes in Overuse Injured Recreational Runners Using Floating Heel Shoes: Preliminary Results of a Randomised Control Trial

Foot-strike and the associated load rate are factors related to overuse injuries in runners. The purpose of this study was to analyse structural and functional changes in runners using floating heel running shoes, compared with runners using conventional footwear. A randomised control trial was conducted. Twenty runners with overuse injuries were followed over a 12-week gait retraining programme using floating heel running shoes or their conventional footwear. Pain was measured with pressure pain thresholds (PPTs), structural changes were measured with ultrasonography, and severity and impact of injury was scored on the Oslo Sports Trauma Research Centre Overuse Injury Questionnaire (OSTRC-O). Statistical differences were found between groups after the intervention (p < 0.001), with a medium size effect SE = 0.8, and the floating heel running shoes group reached higher PPTs values. Participants using floating heel running shoes showed higher OSTRC-O scores than those using their conventional footwear (p < 0.05), with higher scores after the intervention (p < 0.05). A 12-week gait retraining programme using floating heel running shoes had positive effects on the injury recovery process when compared to the use of conventional footwear, with significant differences in terms of pain and impact on sports activity.

Age-related increase in muscle stiffness is muscle length dependent and associated with muscle force in senior females

Background

In aging, muscle stiffness is considered as one of the factors associated with the reduction of force generation capability. There have been inconsistent findings on age-related alteration in the passive stiffness of quadriceps muscle in the female adults. Thus, the aim of this study was to determine the effect of aging on the shear moduli of the superficial muscle heads of the quadriceps and to explore its relationship with knee extension force.

Methods

Passive shear moduli of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) were measured at rest using shear wave elastography in 20 young and 20 senior female adults. Measurements were repeated at four knee joint positions, that is, 30°, 60°, 90°, and 105° of knee flexion. Maximal isometric voluntary knee extension force was assessed at 30°, 60°, and 90° of knee flexion.

Results

As per our findings, senior adults were determined to have significantly higher passive muscle shear moduli in the RF (by 34% – 68%; all p < 0.05) and the VL muscle heads (by 13%–16%, all p < 0.05) at and beyond 60° of knee flexion. Age-related increase in the VM was evident at 105° knee flexion (by11%, p = 0.020). The RF shear modulus was negatively correlated to the maximal isometric voluntary contraction force measured at 60° (r =  − 0.485, p = 0.030) in senior adults.

Conclusions

Senior female adults had greater passive stiffness at the superficial muscle heads of the quadriceps muscles when measured at long muscle length. Among the senior female adults, the passive stiffness of RF has been determined to have a negative association with the knee extensor force only at 60° knee flexion. No significant association was noted for other angles and muscles.

Validity of ultrasonography-derived predictions for estimating skeletal muscle volume: a systematic literature review

Background

The amount of muscle volume (MV) varies between individuals and is important for health, well-being and performance. Therefore, the monitoring of MV using different imaging modalities is important. Magnetic resonance imaging (MRI) is considered the gold standard, but is not always easily accessible, and the examinations are expensive. Ultrasonography (US) is a much less expensive imaging method widely used to measure changes in muscle thickness (MT). Whether MT may translate into MV needs further investigation.

Purpose

The aim of this review is to clarify whether US-derived equations based on MT predict MV based on MRI.

Methods

A systematic literature review was conducted according to the PRISMA statement, searching the electronic databases PubMed, CINAHL and Web of Science, for currently published equations to estimate MV with US.

Results

The literature search resulted in 363 citations. Twelve articles met the eligibility criteria. Ten articles scored eight out of eleven on QUADAS and two scored nine. Thirty-six prediction equations were identified. R values ranged between 0.53 and 0.961 and the standard error of the estimate (SEE) ranged between 6 and 12% for healthy adult populations, and up to 25.6% for children with cerebral palsy. Eight studies evaluated the results with a Bland–Altman plot and found no systematic errors. The overall strength and quality of the evidence was rated “low quality” as defined by the GRADE system.

Conclusions

The validity of US-derived equations based on MT is specific to the populations from which it is developed. The agreement with MV based on MRI is moderate with the SEE ranging between 6 and 12% in healthy adult populations. Suggestions for future research include investigations as to whether testing positions or increasing the number of measuring sites could improve the validity for prediction equations.

The effect of regional quadriceps anatomical parameters on angle-specific isometric torque expression

The length–tension relationship affects knee extension performance; however, whether anatomical variations in different quadriceps regions affect this relationship is unknown. Regional (proximal, middle, distal) quadriceps thickness (MT), pennation angle, and fascicle length of 24 males (48 limbs) were assessed via ultrasonography. Participants also performed maximal voluntary isometric torque (MVIT) assessments at 40°, 70°, and 100° of knee flexion. Measures were recorded on 3 separate occasions. Linear regression models predicting angle-specific torque from regional anatomy provided adjusted simple and multiple correlations (√adjR2) with bootstrapped compatibility limits to assess magnitude. Middle vastus lateralis MT and MVIT at 100° (√adjR2 = 0.64) was the largest single correlation, with distal vastus lateralis MT having the greatest mean correlations regardless of angle (√adjR2 = 0.61 ± 0.05, mean ± SD). Lateral distal MT and architecture had larger (Δ√adjR2 = 0.01 to 0.43) single and multiple correlations with MVIT than the lateral proximal (√adjR2 = 0.15 to 0.69 vs −0.08 to 0.65). Conversely, middle anterior MT had greater (Δ√adjR2 = 0.08 to 0.38) single and multiple correlations than proximal MT (√adjR2 = 0.09 to 0.49 vs −0.21 to 0.14). The length–tension relationship was trivially affected by regional quadriceps architecture. The middle and distal quadriceps were the strongest predictors of MVIT at all joint angles. Therefore, researchers may wish to focus on middle and distal lateral quadriceps anatomy when performing ultrasonographic evaluations.

Novelty: The length–tension relationship is minimally affected by regional quadriceps anatomical parameters. Middle and distal vastus lateralis and lateral vastus intermedius anatomy were consistently the best predictors of torque. Practitioners may focus their assessments on the middle and distal regions of the lateral quadriceps’ musculature.

Assessing the Reliability of Handheld Dynamometry and Ultrasonography to Measure Quadriceps Strength and Muscle Thickness in Children, Adolescents, and Young Adults

Aims: Muscle strength testing is a core aspect in the pediatric physical and occupational therapy clinical examination and evaluation, and quadriceps muscle strength is associated with the ability to perform gross motor skills. The aim of this study was to assess the reliability of handheld dyamometry (HHD) and ultrasonography to measure quadriceps muscle strength and thickness in children, adolescents, and young adults. Methods: In 30 participants (6-26 years), without motor impairment, quadriceps strength was measured with HHD in seated and supine with the knee flexed to 90° and 35°. Rectus femoris (RF) and vastus lateralis (VL) muscle thickness was measured using ultrasonography. Typical error of measurement (TEM), coefficient of variation (CV%), and intra-class correlation coefficient (ICC) were used to assess the error and reliability of measures. Results: The average CV% among three trials of strength testing was 7.07%-9.94% and improved when using the top two trials (4.49%-5.61%). The average TEM was 2.21 Nm for strength and 0.03 cm for muscle thickness. Intra-rater and inter-rater reliability of muscle thickness was good to excellent (0.91-1.00).Conclusions: The results of this study suggest quadriceps muscle strength and thickness measurements using HHD and ultrasonography are reliable in children, adolescents, and young adults.

Effects of long-term athletic training on muscle morphology and tendon stiffness in preadolescence: association with jump performance

Purpose

Evidence on training-induced muscle hypertrophy during preadolescence is limited and inconsistent. Possible associations of muscle strength and tendon stiffness with jumping performance are also not investigated. We investigated the thickness and pennation angle of the gastrocnemius medialis muscle (GM), as indicators for potential muscle hypertrophy in preadolescent athletes. Further, we examined the association of triceps surae muscle–tendon properties with jumping performance.

Methods

Eleven untrained children (9 years) and 21 similar-aged artistic gymnastic athletes participated in the study. Muscle thickness and pennation angle of the GM were measured at rest and muscle strength of the plantar flexors and Achilles tendon stiffness during maximum isometric contractions. Jumping height in squat (SJ) and countermovement jumps (CMJ) was examined using a force plate. We evaluated the influence of normalised muscle strength and tendon stiffness on jumping performance with a linear regression model.

Results

Muscle thickness and pennation angle did not differ significantly between athletes and non-athletes. In athletes, muscle strength was greater by 25% and jumping heights by 36% (SJ) and 43% (CMJ), but Achilles tendon stiffness did not differ between the two groups. The significant predictor for both jump heights was tendon stiffness in athletes and normalised muscle strength for the CMJ height in non-athletes.

Conclusion

Long-term artistic gymnastics training during preadolescence seems to be associated with increased muscle strength and jumping performance but not with training-induced muscle hypertrophy or altered tendon stiffness in the plantar flexors. Athletes benefit more from tendon stiffness and non-athletes more from muscle strength for increased jumping performance.

Bilateral Comparisons of Quadriceps Thickness after Anterior Cruciate Ligament Reconstruction

Background and objectives: Anterior cruciate ligament reconstruction (ACLR) often results in quadricep atrophy. The purpose of this study was to compare the bilateral thickness of each quadricep component before and after ACLR. Materials and Methods: Cross-sectional study design. In 14 patients who underwent ACLR, bilateral quadricep muscle thicknesses were measured using a portable ultrasound device, 1 h before and 48–72 h after ACLR. Two-way analysis of variance (ANOVA) was used to compare muscle thickness pre- and post-ACLR between the limbs. Results: The primary finding was that the vastus intermedius (VI) muscle was significantly smaller in the reconstructed limb after ACLR compared to that in the healthy limb (Reconstructed limb; RCL = Pre-operated (PRE): 19.89 ± 6.91 mm, Post-operated(POST): 16.04 ± 6.13 mm, Healthy limb; HL = PRE: 22.88 ± 6.07, POST: 20.90 ± 5.78 mm, F = 9.325, p = 0.009, η²p = 0.418). Conclusions: The results represent a selective surgical influence on the quadricep muscle thickness. These findings highlight the need of advanced strengthening exercises in order to restore VI thickness after ACLR.

Acute Effects of Open Kinetic Chain Exercise Versus Those of Closed Kinetic Chain Exercise on Quadriceps Muscle Thickness in Healthy Adults

This study aimed to compare immediate changes in the thickness of the rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL), vastus medialis (VM), and vastus medialis oblique (VMO) muscles after open kinetic chain exercise (OKCE) and closed kinetic chain exercise (CKCE) and identify the effect of both exercise types on each quadricep muscle for early rehabilitation to prevent knee joint injury. Twenty-six healthy participants (13 males and 13 females) were randomly divided into the OKCE (n = 13) and CKCE (n = 13) groups. The thickness of their quadriceps muscles was measured using a portable ultrasonic imaging device before and after exercise in the sequence RF, VI, VL, VM, and VMO. A two-way repeated measures analysis of variance was used to compare the thickness of each component of the quadriceps muscles between the two groups. The thickness of the RF, VL, VM, and VMO muscles increased after OKCE, and the thickness of the VI muscle showed the greatest increase with a medium–large effect size (F = 8.52, p = 0.01, and d = 0.53). The thickness of the VI, VL, VM, and VMO muscles increased after CKCE, and the VMO muscle had the largest effect size (F = 11.71, p = 0.00, and d = 1.02). These results indicate that the thickness of the quadriceps muscles can be selectively improved depending on the type of exercise.

Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial

BACKGROUND

We implemented a blood flow restriction resistance training (BFR-RT) intervention during an 8-week rehabilitation programme in anterior cruciate ligament reconstruction (ACLR) patients within a National Health Service setting.

OBJECTIVE

To compare the effectiveness of BFR-RT and standard-care traditional heavy-load resistance training (HL-RT) at improving skeletal muscle hypertrophy and strength, physical function, pain and effusion in ACLR patients following surgery.

METHODS

28 patients scheduled for unilateral ACLR surgery with hamstring autograft were recruited for this parallel-group, two-arm, single-assessor blinded, randomised clinical trial following appropriate power analysis. Following surgery, a criteria-driven approach to rehabilitation was utilised and participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM. Participants completed 8 weeks of biweekly unilateral leg press training on both limbs, totalling 16 sessions, alongside standard hospital rehabilitation. Resistance exercise protocols were designed consistent with standard recommended protocols for each type of exercise. Scaled maximal isotonic strength (10RM), muscle morphology of the vastus lateralis of the injured limb, self-reported function, Y-balance test performance and knee joint pain, effusion and range of motion (ROM) were assessed at pre-surgery, post-surgery, mid-training and post-training. Knee joint laxity and scaled maximal isokinetic knee extension and flexion strength at 60°/s, 150°/s and 300°/s were measured at pre-surgery and post-training.

RESULTS

Four participants were lost, with 24 participants completing the study (12 per group). There were no adverse events or differences between groups for any baseline anthropometric variable or pre- to post-surgery change in any outcome measure. Scaled 10RM strength significantly increased in the injured limb (104 ± 30% and 106 ± 43%) and non-injured limb (33 ± 13% and 39 ± 17%) with BFR-RT and HL-RT, respectively, with no group differences. Significant increases in knee extension and flexion peak torque were observed at all speeds in the non-injured limb with no group differences. Significantly greater attenuation of knee extensor peak torque loss at 150°/s and 300°/s and knee flexor torque loss at all speeds was observed with BFR-RT. No group differences in knee extensor peak torque loss were found at 60°/s. Significant and comparable increases in muscle thickness (5.8 ± 0.2% and 6.7 ± 0.3%) and pennation angle (4.1 ± 0.3% and 3.4 ± 0.1%) were observed with BFR-RT and HL-RT, respectively, with no group differences. No significant changes in fascicle length were observed. Significantly greater and clinically important increases in several measures of self-reported function (50-218 ± 48% vs. 35-152 ± 56%), Y-balance performance (18-59 ± 22% vs. 18-33 ± 19%), ROM (78 ± 22% vs. 48 ± 13%) and reductions in knee joint pain (67 ± 15% vs. 39 ± 12%) and effusion (6 ± 2% vs. 2 ± 2%) were observed with BFR-RT compared to HL-RT, respectively.

CONCLUSION

BFR-RT can improve skeletal muscle hypertrophy and strength to a similar extent to HL-RT with a greater reduction in knee joint pain and effusion, leading to greater overall improvements in physical function. Therefore, BFR-RT may be more appropriate for early rehabilitation in ACLR patient populations within the National Health Service.

The Effects of Anterior Cruciate Ligament Reconstruction on Individual Quadriceps Muscle Thickness and Circulating Biomarkers

Anterior cruciate ligament reconstruction (ACLR) frequently results in quadriceps atrophy. The present study investigated the effect of ACLR on the muscle thickness of the different constituent muscles of the quadriceps and circulating biomarkers related to muscle atrophy and hypertrophy. Fourteen subjects underwent anterior cruciate ligament reconstruction following injury. Quadriceps muscle thicknesses were measured using ultrasound, and circulating biomarkers in the blood were measured using enzyme-linked immunosorbent assays (ELISAs) at the preoperative visit (PRE) and at two postoperative visits (PO1, PO2) in the early stages post-surgery. Differences between time points were analyzed using one-way repeated measures analysis of variance (ANOVA) tests. The most important finding was that severe muscle atrophy occurred in the vastus intermedius (VI) after ACLR (PRE: 20.45 ± 6.82 mm, PO1: 16.05 ± 6.13 mm, PO2: 13.18 ± 4.7 mm, F = 59.0, p < 0.001). Furthermore, the myostatin level was slightly increased, and IGF-1 was significantly reduced throughout the entire period. Therefore, we suggest that inducing selective hypertrophy in the vastus intermedius during the process of rehabilitation would be important for athletes and individuals who engage in explosive sports. Moreover, inhibiting myostatin level increases and maintaining IGF-1 levels in the early phase of recovery after ACLR to prevent muscle atrophy may provide a pharmaceutical option for rehabilitation after anterior cruciate ligament injury.

In vivo muscle morphology comparison in post-stroke survivors using ultrasonography and diffusion tensor imaging

Skeletal muscle architecture significantly influences the performance capacity of a muscle. A DTI-based method has been recently considered as a new reference standard to validate measurement of muscle structure in vivo. This study sought to quantify muscle architecture parameters such as fascicle length (FL), pennation angle (PA) and muscle thickness (tm) in post-stroke patients using diffusion tensor imaging (DTI) and to quantitatively compare the differences with 2D ultrasonography (US) and DTI. Muscle fascicles were reconstructed to examine the anatomy of the medial gastrocnemius, posterior soleus and tibialis anterior in seven stroke survivors using US- and DTI-based techniques, respectively. By aligning the US and DTI coordinate system, DTI reconstructed muscle fascicles at the same scanning plane of the US data can be identified. The architecture parameters estimated based on two imaging modalities were further compared. Significant differences were observed for PA and tm between two methods. Although mean FL was not significantly different, there were considerable intra-individual differences in FL and PA. On the individual level, parameters measured by US agreed poorly with those from DTI in both deep and superficial muscles. The significant differences in muscle parameters we observed suggested that the DTI-based method seems to be a better method to quantify muscle architecture parameters which can provide important information for treatment planning and to personalize a computational muscle model.

Effects of neuromuscular training on pain intensity and self-reported functionality for patellofemoral pain syndrome in runners: study protocol for a randomized controlled clinical trial

BACKGROUND

Patellofemoral pain syndrome (PFPS) is common and affects approximately 15% of individuals at different ages and activity levels. As a non-surgical intervention, physiotherapy is widely used to treat PFPS. Neuromuscular training exercise is one of the most effective methods for decreasing musculoskeletal pain and improving knee function. However, the effectiveness of neuromuscular training exercise for treating PFPS is not without argument. The purpose of this study is to evaluate the effect of neuromuscular training exercise on patellofemoral pain and whether the neuromuscular training exercise have more advantage effects than taping and health education.

METHODS

We will operate a prospective, single-blind, randomized controlled trial of 60 patients with patellofemoral pain. Individuals will be indiscriminately assigned to two intervention groups and a health education group. The neuromuscular training exercise which includes the muscle strength training, balance training and knee joint proprioception training, and taping group will use "Y" and "I" type taping on the participants three times a week for three months. The health education group will be given education lectures once each week and which last for three months. The primary outcome measures include the adverse events, visual analog scale for pain, and Anterior Knee Pain Scale Index, which is a knee function self-report questionnaire to evaluate the function of the knee especially for PFPS patients. The secondary outcome measures are the muscle strength and endurance of knee joint flexion and extensor muscles, knee joint proprioception, muscle thickness of the quadriceps femoris, knee function ability, and quality of life. We will manage the intention-to-treat analysis for individuals who will withdraw from this study.

DISCUSSION

According to previous studies, neuromuscular training exercise and the taping method are effective treatment for PFPS patients. In this study, we will perform a neuromuscular training exercise for patients with PFPS. We believe that this study may prove the effectiveness of neuromuscular training exercise in treating PFPS.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800014995 . Registered on 27 February 2018.

Ultrasound evaluation of the quadriceps muscles in pronated foot posture

OBJECTIVE

The main goal of this study was to investigate the size of all portions of the quadriceps muscles in individuals with pronated foot posture compared to normal foot posture using ultrasound imaging.

DESIGN

Twenty nine females with pronated foot posture and 29 age-, body weight-, body height-matched females with normal foot posture were recruited from university communities. The muscle thicknesses of the rectus femoris (RF), vastus medialis (VM), vastus medialis oblique (VMO), vastus lateralis (VL) and vastus intermedius (VI) were measured using ultrasound imaging.

RESULTS

The thicknesses of the RF and VMO were significantly smaller in individuals with pronated foot posture compared to normal foot posture (p<0.05). No significant differences were observed in the VM, VL, and VI muscle thicknesses in both groups.

CONCLUSION

Based on the results of the present study, it seems that besides the foot and lower leg muscles, an integrated assessment of proximal knee muscles, especially quadriceps, is required in individuals with pronated foot posture.

The effects of early neurodevelopmental Bobath approach and mobilization on quadriceps muscle thickness in stroke patients

Background/aim

Following stroke, damage to the central nervous system and adaptive changes in muscle tissue are factors responsible for the loss of muscle strength. Even though it is suggested that early physiotherapy and mobilization prevent structural adaptive changes in muscle tissue, studies regarding this issue are insufficient. The aim of this study is to investigate the effects of early physiotherapy and mobilization on quadriceps muscle thickness (QMT) in stroke patients.

Materials and methods

Twelve stroke patients who were admitted to the neurology intensive care unit and 13 healthy controls were included in the study. QMT was examined at admission and discharge for each subject. Additionally, functional extremity movements, balance, and functional ambulation status were evaluated with the Stroke Rehabilitation Assessment of Movement Scale (STREAM). All of the patients were mobilized as early as possible by a physiotherapist and included in a treatment program consisting of the neurodevelopmental Bobath approach.

Results

The patients’ QMT values at admission and discharge were found to be similar to those of the healthy control group (P > 0.05). When the patients’ QMT at the time of admission and discharge were compared, it was seen that the affected side and the nonaffected side were similar (P > 0.05). Additionally, when the admission and discharge results were compared, improvements in functional extremity movements, balance, and functional ambulation levels were observed (P < 0.05).

Conclusion

It can be seen that QMT can be preserved and functional improvements can be provided through intense physiotherapy and mobilization initiated in the early period following stroke.

Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players

OBJECTIVES

To determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players.

DESIGN

Experimental, randomized trial.

METHODS

Twenty-two resistance-trained ice hockey players (18±1year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n=11) or traditional resistance training (TRAD; n=11). Participants underwent supervised progressive resistance training for 8 weeks (2-3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement.

RESULTS

Similar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11-17%, P<0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P=0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P=0.01) and rectus femoris muscles (P=0.03).

CONCLUSIONS

Both modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players.

The challenges of muscle biopsy in a community based geriatric population

Objectives

To describe the difficulties of obtaining muscle samples using a Bergstrom needle technique in a frail older adult population. The data were obtained from a study primarily investigating immunosenescence in frailty. An intended research technique was skeletal muscle biopsy in a small subset of participants to investigate muscle morphology and local inflammatory factors.

Results

Forty healthy older adults and 37 frail older adults were considered for a Bergstrom needle muscle biopsy. Of these, 17.5% of healthy older adults and 94.6% of the frail older adults had single or multiple participant factors resulting in a contra-indication to muscle biopsy. 40.7% of healthy older female participants were at risk of a failed muscle biopsy due to low muscle mass. Considering only muscle mass muscle biopsy would have been successful in 18.7% of the frail older women and 21.4% of the frail older men. In this population, muscle biopsy was not feasible because of contra-indications in the majority of participants. This questions whether a biopsy sample obtained from frail older individuals, is actually representative of this population and supports the need to disclose biopsy failure rate in this population.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3947-8) contains supplementary material, which is available to authorized users.

Correlation of physical function with the thickness of multiple muscles of the quadriceps femoris in community-dwelling elderly individuals

Purpose

The purpose of this study was to clarify the reference values of muscle thicknesses by age and to elucidate the association of muscle thickness with physical function in a large group of community-dwelling elderly individuals.

Participants and methods

The muscle thicknesses of the rectus femoris (RF), vastus intermedius (VI), and quadriceps femoris (QF) in 777 of 831 enrolled elderly individuals were measured by ultrasonography, and physical function was measured using knee extension strength (KES), one-legged stance, walking, Timed Up and Go, and grip strength tests. Muscle thickness data were divided by sex and categorized into 5-year age groups. Differences in muscle thickness and KES among the age groups were examined, and correlations between muscle thickness and physical function test results were compared by age. The non-parametric independent two-sample Mann-Whitney U-test, Kruskal-Wallis test, and Spearman's correlation coefficients were used in the statistical analysis.

Results

Thickness of the RF showed fewer significant differences among all groups and less decreases compared to thickness of the VI in older age groups, especially in men. Thicknesses of the RF, VI, and QF correlated with KES in almost all the thicknesses of muscles in the 65-69 and 70-74 years age groups in men and in almost all age groups in women. The decrease in muscle thicknesses and degree of correlations with aging were different between men and women.

Conclusions

Reductions in the thicknesses of the muscles and KES differed by age group and sex. Our results could be used for prescribing exercise in community-dwelling elderly individuals of varying ages.

Effect of strength training combined with antioxidant supplementation on muscular performance

This was a placebo-controlled randomized study that aimed to investigate the effects of strength training (ST) combined with antioxidant supplementation on muscle performance and thickness. Forty-two women (age, 23.8 ± 2.7 years; body mass, 58.7 ± 11.0 kg; height, 1.63 ± 0.1 m) were allocated into 3 groups: vitamins (n = 15), placebo (n = 12), or control (n = 15). The vitamins and placebo groups underwent an ST program, twice a week, for 10 weeks. The vitamins group was supplemented with vitamins C (1 g/day) and E (400 IU/day) during the ST period. Before and after training, peak torque (PT) and total work (TW) were measured on an isokinetic dynamometer, and quadriceps muscle thickness (MT) was assessed by ultrasound. Mixed-factor ANOVA was used to analyze data and showed a significant group × time interaction for PT and TW. Both the vitamins (37.2 ± 5.4 to 40.3 ± 5.6 mm) and placebo (39.7 ± 5.2 to 42.5 ± 5.6 mm) groups increased MT after the intervention (P < 0.05) with no difference between them. The vitamins (146.0 ± 29.1 to 170.1 ± 30.3 N·m) and placebo (158.9 ± 22.4 to 182.7 ± 23.2 N·m) groups increased PT after training (P < 0.05) and PT was higher in the placebo compared with the control group (P = 0.01). The vitamins (2068.3 ± 401.2 to 2295.5 ± 426.8 J) and placebo (2165.1 ± 369.5 to 2480.8 ± 241.3 J) groups increased TW after training (P < 0.05) and TW was higher in the placebo compared with the control group (P = 0.01). Thus, chronic antioxidant supplementation may attenuate peak torque and total work improvement in young women after 10 weeks of ST.

Steps to Enhance Early Recovery After Hematopoietic Stem Cell Transplantation: Lessons Learned From a Physical Activity Feasibility Study

AIMS

This pilot study tested and refined a free-living physical activity intervention. The investigators evaluated the acceptability and feasibility of the intervention after hematopoietic stem cell transplantation and determined preliminary effects on physical activity, fatigue, muscle strength, functional ability, and quality of life.

DESIGN

This pilot study used a 1-group, pretest-posttest design.

METHODS

The free-living physical activity intervention consisted of an education component and 6 weeks of gradually increasing physical activity after discharge from the hospital. The intervention was designed to increase steps by 10% weekly. Subjects were assessed before transplantation and during the seventh week after discharge from the hospital after completing the intervention. Pretest-posttest scores were analyzed with paired t tests.

RESULTS

Subject wore the physical activity tracker for an average of 38 of 42 days and met their physical activity goals 57% of the time. Subjects reported significantly less physical fatigue after the free-living physical activity intervention compared with baseline (P = .05). Improvements in quality of life approached significance (P = .06).

CONCLUSION

The findings demonstrate that the free-living physical activity intervention implemented during the very early recovery period after transplantation is feasible and acceptable. The intervention potentially reduces fatigue and improves quality of life. The positive results must be interpreted cautiously given the pilot nature of the study. The evidence supports continued investigation.

Cross-sectional comparison of age-related changes in the quadriceps femoris in Japanese basketball players

Background This study examines age-related changes in the quadriceps femoris (QF), subdivided into the vastus medialis oblique (VMO), vastus medialis (VM), rectus femoris (RF), vastus intermedius (VI) and vastus lateralis (VL) in basketball players. Subjects Seventy male basketball players were divided into four groups according to age (12-13, 14-15, 16-17, and 18-20 years). Methods Ultrasonography was used to measure muscle architecture of the VMO, VM, RF, VI and VL. We created cubic approximate expressions and calculated inflexion points to evaluate peak growth age of each muscle head. Results Significant interactions were observed for all QF parts (p < 0.01-0.001). Muscle thickness (MT) in all QF parts was significantly lower in 12-13-year olds than in 18-20-year olds (p < 0.01-0.001). Significant differences were recognised between 12-13 and 16-17-year olds in VM (p < 0.001), RF (p < 0.001) and VL (p = 0.007). MT was significantly lower in 14-15-year olds than in 16-17-year olds in the VM (p = 0.007) and RF (p = 0.026) and in 18-20 year olds in the VM (p < 0.001), RF (p = 0.036) and VI (p < 0.001). Peak growth age was estimated for each QF part (VMO, 155.0 months; VM, 187.8 months; RF, 212.2 months, VI, 188.9 months; VL, 181.1 months). Conclusion QF parts have different growth rates due to differing functions in each muscle head.

Hip rate of force development and strength are impaired in females with patellofemoral pain without signs of altered gluteus medius and maximus morphology

OBJECTIVES

To compare rate of force development (RFD) and isometric muscle strength of the hip abductors and extensors; and the thickness and the amount of non-contractile tissue of the gluteus medius and maximus between females with and without patellofemoral pain (PFP).

DESIGN

Cross-sectional study.

METHODS

Fifty-four physically active females (27 with PFP and 27 healthy individuals) were studied. Hip muscle isometric strength and RFD was evaluated using isokinetic dynamometry. RFD was measured until 30%, 60%, and 90% of the maximal isometric torque (MIT). Hip muscle morphology was evaluated using ultrasonography.

RESULTS

The PFP group possessed slower RFD compared to the control group by 33% for hip abductors until 90%MIT (-0.23%/ms, 95%CI -0.44 to -0.02, ES=0.59); by 51% for hip extensors until 30%MIT (-0.42%/ms, 95%CI -0.66 to -0.18, ES=0.97); and by 55% for hip extensors until 60%MIT (-0.36%/ms, 95%CI -0.60 to -0.12, ES=0.81). The PFP group possessed reduced isometric torque compared to the control group by 10% for hip abduction (-16.0Nm/kg×100, 95% CI -30.2 to -1.9, ES=0.61) and by 15% for hip extension (-30.1Nm/kg×100, 95%CI -51.4 to -8.9, ES=0.76). No significant between group differences for the thickness and the amount of non-contractile tissue of the gluteus medius and maximus were identified.

CONCLUSIONS

Females with PFP have deficits in isometric strength and RFD in hip abduction and extension. RFD deficits are greater than strength deficits which may highlight their potential importance. Hip muscle strength and RFD deficits do not appear to be explained by muscle thickness or proportion of non-contractile tissue of the gluteal musculature as measured by ultrasound.

Lower extremity muscle structure in incomplete spinal cord injury: a comparison between ultrasonography and magnetic resonance imaging

INTRODUCTION

Ultrasound (US) measures of muscle thickness are used in the management and monitoring of muscle changes during rehabilitation, but it is unknown how this measure compares to magnetic resonance imaging (MRI) measures of muscle cross-sectional area (CSA) in patients with spinal cord injury (SCI).

CASE PRESENTATION

Six participants with incomplete SCI underwent US imaging and MRI of their gastrocnemius and tibialis anterior (TA) muscles.

DISCUSSION

Significant correlations were found between US muscle thickness and MRI CSA in the gastrocnemius (R=0.91, P<0.001), and TA muscles (R=0.58, P<0.05). US muscle thickness in the gastrocnemius and TA of patients with incomplete SCI may be used as a cheaper alternative measure of CSA as measured using MRI, and this measure may be clinically useful to track progress in muscle gains during rehabilitation.

Omega-3 Fatty Acids and Vitamin D in Immobilisation: Part A- Modulation of Appendicular Mass Content, Composition and Structure

OBJECTIVES

Muscle size decreases in response to short-term limb immobilisation. This study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would attenuate immobilisation-induced changes in muscle characteristics.

DESIGN

The study used a randomised, double-blind, placebo-controlled design.

SETTING

The study took part in a laboratory setting.

PARTICIPANTS

Twenty-four male and female healthy participants, aged 23.0±5.8 years.

INTERVENTION

The non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily).

MEASUREMENTS

Muscle and sub-cutaneous adipose thickness (B-mode ultrasonography), body composition (DXA) and arm girth (anthropometry) were measured before immobilisation, immediately on removal of the sling and two weeks after re-mobilisation.

RESULTS

Muscle thickness (-5.4±4.3%), upper and lower arm girth (-1.3±0.4 and -0.8±0.8%, respectively), lean mass (-3.6±3.7%) and bone mineral content (BMC) (-2.3±1.5%) decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of group, ω-3 and vitamin D supplementation showed trends (p>0.05) towards attenuating the decreases in muscle thickness, upper/lower arm girths and BMC observed in the placebo group. The ω-3 supplementation group demonstrated a non-significant attenuation of the decrease in DXA quantified lean mass observed in the placebo group. Sub-cutaneous adipose thickness increased in the placebo group (P<0.05). ω-3 and vitamin D both blunted this response, with ω-3 having a greater effect (P<0.05). All parameters had returned to baseline values at the re-mobilisation phase of the study.

CONCLUSION

Overall, at the current doses, ω-3 and vitamin D supplementation only attenuated one of the changes associated with non-injurious limb immobilisation. These findings would necessitate further research into either a) supplementation linked to injury-induced immobilisation, or b) larger doses of these supplements to confirm/refute the physiological reserve potential of the two supplements.

Strength Training to Enhance Early Recovery after Hematopoietic Stem Cell Transplantation

Intensive cancer treatment followed by hematopoietic stem cell transplantation (HCT) results in moderate to severe fatigue and physical inactivity, leading to diminished functional ability. The purpose of this study was to determine the efficacy of an exercise intervention, strength training to enhance early recovery (STEER), on physical activity, fatigue, muscle strength, functional ability, and quality of life after HCT. This single-blind, randomized clinical trial compared strength training (n = 33) to usual care plus attention control with health education (UC + AC with HE) (n = 34). Subjects were stratified by type of transplantation and age. STEER consisted of a comprehensive program of progressive resistance introduced during hospitalization and continued for 6 weeks after hospital discharge. Fatigue, physical activity, muscle strength, functional ability, and quality of life were assessed before HCT hospital admission and after intervention completion. Data were analyzed using split-plot analysis of variance. Significant time × group interactions effects were noted for fatigue (P = .04). The STEER group reported improvement in fatigue from baseline to after intervention whereas the UC + AC with HE group reported worsened fatigue from baseline to after intervention. Time (P < .001) and group effects (P = .05) were observed for physical activity. Physical activity declined from baseline to 6 weeks after hospitalization. The STEER group was more physically active. Functional ability tests (timed stair climb and timed up and go) resulted in a significant interaction effect (P = .03 and P = .05, respectively). Subjects in the UC + AC with HE group were significantly slower on both tests baseline to after intervention, whereas the STEER group's time remained stable. The STEER group completed both tests faster than the UC + AC with HE group after intervention. Study findings support the use of STEER after intensive cancer treatment and HCT. Strength training demonstrated positive effects on fatigue, physical activity, muscle strength, and functional ability. The exact recovery patterns between groups and over time varied; the STEER group either improved or maintained their status from baseline to after intervention (6 weeks after hospital discharge) whereas the health education group generally declined over time or did not change.

Ultrasound Assessment of the Rectus Femoris Cross-Sectional Area: Subject Position Implications

Ultrasonic measurement of the rectus femoris (RF) is a novel, proxy measure for muscle strength. The impact of hip flexion/head of bed positioning on RF cross-sectional area (CSA) has not been fully explored. This study describes and compares differences in RF CSA across four degrees of hip flexion. This repeated-measures, comparative study enrolled healthy, pre-menopausal women (n = 20). RF CSA of the dominant leg was measured using the SonoSite M-Turbo ultrasound system with the head of bed at 0°, 20°, 30°, and 60°. One-way repeated measures indicated significant differences in RF CSA, F(3, 17) = 14.18, p < .001, with variation in hip flexion/head of bed elevation and significant RF CSA differences between: (a) 0° and 20°, (b) 0° and 30°, (c) 0° and 60°, and (d) 20° and 60°. Standardizing patient positioning when conducting ultrasonic measurement of RF CSA is vital for researchers who assess muscle mass.

Atrophy of the Quadriceps Is Not Isolated to the Vastus Medialis Oblique in Individuals With Patellofemoral Pain

STUDY DESIGN

Cross-sectional. Objectives To determine if quadriceps atrophy was present in people with patellofemoral pain (PFP), and whether the vastus medialis oblique (VMO) was selectively involved.

BACKGROUND

Despite the lack of research investigating individual quadriceps muscle size in individuals with PFP, it has been suggested that selective atrophy of the VMO relative to the vastus lateralis could be associated with PFP.

METHODS

The quadriceps muscle sizes of 35 participants with PFP (22 with unilateral and 13 with bilateral symptoms) and 35 asymptomatic control participants matched for age and sex were measured using real-time ultrasound. The thicknesses of the VMO, vastus lateralis, vastus medialis, rectus femoris, and vastus intermedius were measured. Paired-samples t tests were used to compare muscle thickness between limbs in those with unilateral PFP, and independent t tests were used to compare muscle thickness between groups with and without PFP. Results In those with unilateral PFP, the thickness of all portions of the quadriceps muscle was statistically smaller in the symptomatic compared to the asymptomatic limb: VMO (P = .038), vastus medialis (P<.001), vastus lateralis (P = .005), vastus intermedius (P = .013), and rectus femoris (P = .045). No difference was found in thickness of any of the portions of the quadriceps on the affected side of people with PFP compared to asymptomatic controls: VMO (P = .148), vastus medialis (P = .474), vastus lateralis (P = .122), vastus intermedius (P = .466), and rectus femoris (P = .508).

CONCLUSION

Atrophy of all portions of the quadriceps muscles is present in the affected limb of people with unilateral PFP. There was no atrophy of the quadriceps in individuals with PFP compared to those without pathology. Selective atrophy of the VMO relative to the vastus lateralis was not identified in people with PFP.

Skeletal muscle hypertrophy adaptations predominate in the early stages of resistance exercise training, matching deuterium oxide-derived measures of muscle protein synthesis and mechanistic target of rapamycin complex 1 signaling

Resistance exercise training (RET) is widely used to increase muscle mass in athletes and also aged/cachectic populations. However, the time course and metabolic and molecular control of hypertrophy remain poorly defined. Using newly developed deuterium oxide (D2O)-tracer techniques, we investigated the relationship between long-term muscle protein synthesis (MPS) and hypertrophic responses to RET. A total of 10 men (23 ± 1 yr) undertook 6 wk of unilateral (1-legged) RET [6 × 8 repetitions, 75% 1 repetition maximum (1-RM) 3/wk], rendering 1 leg untrained (UT) and the contralateral, trained (T). After baseline bilateral vastus lateralis (VL) muscle biopsies, subjects consumed 150 ml D2O (70 atom percentage; thereafter 50 ml/wk) with regular body water monitoring in saliva via high-temperature conversion elemental analyzer:isotope ratio mass spectrometer. Further bilateral VL muscle biopsies were taken at 3 and 6 wk to temporally quantify MPS via gas chromatography:pyrolysis:isotope ratio mass spectrometer. Expectedly, only the T leg exhibited marked increases in function [i.e., 1-RM/maximal voluntary contraction (60°)] and VL thickness (peaking at 3 wk). Critically, whereas MPS remained unchanged in the UT leg (e.g., ∼1.35 ± 0.08%/d), the T leg exhibited increased MPS at 0-3 wk (1.6 ± 0.01%/d), but not at 3-6 wk (1.29 ± 0.11%/d); this was reflected by dampened acute mechanistic target of rapamycin complex 1 signaling responses to RET, beyond 3 wk. Therefore, hypertrophic remodeling is most active during the early stages of RET, reflecting longer-term MPS. Moreover, D2O heralds promise for coupling MPS and muscle mass and providing insight into the control of hypertrophy and efficacy of anabolic interventions.