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An interesting finding from eccentric exercise training interventions is the presence of muscle hypertrophy without changes in maximum concentric strength and/or power. The lack of improvements in concentric strength and/or power could be due to long lasting suppressive effects on muscle force production following eccentric training. Thus, improvements in concentric strength and/or power might not be detected until muscle tissue has recovered (e. g., several weeks post-training). We evaluated alterations in muscular structure (rectus-femoris, RF, and vastus lateralis, VL, thickness and pennation angles) and maximum concentric cycling power (Pmax) 1-week following 8-weeks of eccentric cycling training (2×/week; 5-10.5 min; 20-55% of Pmax). Pmax was assessed again at 8-weeks post-training. At 1 week post-training, RF and VL thickness increased by 24±4% and 13±2%, respectively, and RF and VL pennation angles increased by 31±4% and 13±1%, respectively (all P<0.05). Compared to pre-training values, Pmax increased by 5±1% and 9±2% at 1 and 8 weeks post-training, respectively (both P<0.05). These results demonstrate that short-duration high-intensity eccentric cycling can be a time-effective intervention for improving muscular structure and function in the lower body of healthy individuals. The larger Pmax increase detected at 8-weeks post-training implies that sufficient recovery might be necessary to fully detect changes in muscular power after eccentric cycling training., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objectives: Soldiers lose muscle and bone density during sustained operations. We investigated the impact of β-hydroxy-β-methylbutyrate (HMB) on bone properties, muscle mass, and markers of skeletal muscle regeneration under simulated military sustained operations., Methods: Male mice were divided into four groups (10/group): (1) ALT = ad libitum + trained (1h/d for 3 d/wk); (2) ALTH = ALT + HMB (0.5 g/kg BW/d); (3) C = caloric restricted (-30%) + trained (6h/d, 6d/wk); and (4) CH = C + HMB. Assessments included bone mineral density/content by dual-energy X-ray absorptiometry, muscle wet weight (quadriceps) and expression of selected genes regulating muscle mass and protein turnover. Analysis of variances were used with significance set at p < 0.05., Results: Bone mineral content increased in the ALT group (+16%) and decreased in the C group (-32%). Quadriceps muscle mass was lower in C (-27%) and CH (-19%) compared to ALT and ALTH. Myogenin mRNA expression was higher in C than ALT, ALTH and CH. Protein kinase B (Akt) mRNA expression was higher in both C and CH than ALT and ALTH. Mammalian target of rapamycin expression was higher in CH than ALT and ALTH. Muscle RING-finger protein-1 expression was higher in both C and CH than ALT and ALTH., Conclusion: HMB intake improved bone properties and attenuated the depression of protein synthesis during a simulated sustained military operation., (Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.)

Introduction: Muscle morphology and architecture changes in response to 6 weeks of progressive resistance training were examined in healthy older adults., Methods: In this randomized, controlled design, muscle strength, quality, and architecture were evaluated with knee extension, DEXA, and ultrasound, respectively, in 25 older adults., Results: Resistance training resulted in significant increases in strength and muscle quality of 32% and 31%, respectively. Cross-sectional area of the vastus lateralis increased by 7.4% (p ≤ 0.05). Physiological cross-sectional area (PCSA) of the thigh, a composite measure of muscle architecture, was related significantly to strength (r = 0.57; p ≤ 0.01) and demonstrated a significant interaction after training (p ≤ 0.05). Change in PCSA of the vastus lateralis was associated with change in strength independent of any other measure., Conclusions: Six weeks of resistance training was effective at increasing strength, muscle quality, and muscle morphology in older adult men and women., (Copyright © 2013 Wiley Periodicals, Inc.)

The purpose of this study was to examine the morphological profiles of 4 constituents (vastus lateralis, vastus medialis, vastus intermedius and rectus femoris) of the quadriceps femoris in oarsmen through comparison with non-athletes. T1-weigheted magnetic resonance (MR) images of the thigh were obtained from 14 oarsmen and 19 non-athlete men. From the MR images, serial anatomical cross-sectional areas (ACSAs) and muscle volume of each muscle were determined. The muscle volume of the total quadriceps femoris, vastus lateralis, vastus medialis and vastus intermedius were significantly larger in the oarsmen than in the non-athlete men, whereas that of the rectus femoris was comparable for the 2 groups. The portion of the rectus femoris as a percentage of total quadriceps femoris volume was significantly higher in the non-athlete men than in the oarsmen, and vice versa for the vastus lateralis. The proximal-to-distal and middle-to-distal ACSA ratios in each muscle did not differ between the 2 groups. The present results indicate inferior muscular hypertrophy of the rectus femoris compared to the vasti in oarsmen, and that the vasti are equally hypertrophied along their lengths. This may be due to muscle-specific adaptation to the rowing exercise., (© Georg Thieme Verlag KG Stuttgart · New York.)

This study examined the linearity of the electromyographic (EMG) amplitude vs. concentric and eccentric squat force relationships for monoarticular and biarticular thigh muscles. Fourteen resistance-trained men (mean age ± SD: 22 ± 2 years; estimated thigh muscle cross-sectional area: 221.9 ± 22.7 cm) performed concentric and eccentric squats using a novel testing device from 10 to 90% of their maximum average force. Surface EMG signals were detected from the right vastus lateralis, rectus femoris, and biceps femoris. Linear regression was used to examine the relationships between EMG amplitude and force, and repeated measures analyses of variance were used to assess differences among the muscles. Moderate-to-high coefficients of determination were found for the vastus lateralis for both concentric and eccentric testings (r = 0.587-0.992). For the biceps femoris, the mean linear slope coefficient was significantly greater for concentric vs. eccentric testing (0.044 vs. 0.013 μV RMS·N; p = 0.002; effect size = 1.44). Although EMG amplitude for the vastus lateralis and rectus femoris increased with changes in eccentric force output, the electrical activity of the biceps femoris remained stable. These results demonstrated that the EMG amplitude vs. force relationships for the vastus lateralis were linear, despite the fact that force production during the squat is related to the activation of muscles that must simultaneously function as agonists and antagonists. Our findings for eccentric force testing are in agreement with investigations showing reduced hip extensor activity during concurrent extension at the hip and knee joints.

Objective: The aim of this study was to investigate the effects of isokinetic training program on muscle strength, muscle size and gait parameters after healed pediatric burn., Design: Randomized controlled trial., Subjects: Thirty three pediatric burned patients with circumferential lower extremity burn with total body surface area (TBSA) ranging from 36 to 45%, and ages from 10 to 15 years participated in the study and were randomized into isokinetic group and a control group. Non-burned healthy pediatric subjects were assessed similarly to burned subjects and served as matched healthy controls., Methods: Patients in the isokinetic group (n=16) participated in the isokinetic training program for 12 weeks for quadriceps dominant limb, 3 times per week, at angular velocity 150°/s, concentric mode of contraction, time rest between each set for 3 min, 3 sets/day and control group (n=17) participated in home based physical therapy exercise program without isokinetic., Main Measures: Assessment of quadriceps strength by isokinetic dynamometer, quadriceps size and gait parameters were performed at baseline and at the end of the training period for both groups., Results: Patients in isokinetic group showed a significant improvement in quadriceps strength, quadriceps size and gait parameters as compared with those in the control group. Quadriceps strength and percentage of improvement was 79.25 ± 0.93 Nm (68.40%) for isokinetic group and 51.88 ± 1.31 Nm (9.84%) for the control group. Quadriceps size and percentage of improvement was 31.50 ± 0.89 cm (7.47%) for isokinetic group and 29.26 ± 1.02 cm (1.02%) for the control group. Stride length, step length, velocity and cadence and percentage of improvement for isokinetic group was 135.50 ± 2.82 (53.97%), 63.25 ± 2.97 (63.77%), 135.94 ± 1.65 (81.42%), 137.63 ± 1.36 (66.96%) and for the control group was 94.00 ± 2.69 (6.68%), 43.76 ± 1.34 (15.15%), 81.11 ± 1.91 (8.6%), 90.35 ± 1.32 (9.01%) respectively., Conclusions: Participation in the isokinetic training program resulted in a greater improvement in quadriceps muscle strength, size and gait parameters in pediatric burn., (Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.)

Background: The assumption that the vastus medialis oblique (VMO) is involved in medial patellar stabilisation has led to speculation that patellofemoral pain (PF) may be a result of abnormal patellar tracking, due to weakness or difference in fibre orientation of the VMO. Recent studies have reported that the VMO fibre angle, measured in vivo with ultrasound (US), is reduced in patellofemoral pain (PF) patients. However, the validity of US in measuring this parameter was not investigated and this would inevitably cast doubt on whether the US results are comparable to direct measurement. The aim of this study was to validate the use of ultrasound (US) in measuring VMO fibre angle by comparing results obtained both from US and direct measurement., Methods: The VMO fibre angle was determined in relation to the femoral axis in nine lower limbs from five soft-fixed cadavers, first using US and then by direct measurement., Results: The Pearson correlation coefficient between the two methods was 0.92 (p<0.01) indicating a very strong relationship. The average difference in measurements between the two methods was 0.20. Bland/Altman analysis showed 95% limit of agreement to be between -2.550 and 30, showing minimal discrepancies between results obtained by the two methods., Conclusion: In conclusion, the VMO fibre angle values obtained by the US method were proved to be valid and comparable to those obtained from direct measurement. We show, therefore, that US can be used with confidence to measure VMO fibre angles in the cadaver, and, by implication, in clinical practice., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The impact of using different resistance training (RT) kinematics, which therefore alters RT mechanics, and their subsequent effect on adaptations remain largely unreported. The aim of this study was to identify the differences to training at a longer (LR) compared with a shorter (SR) range of motion (ROM) and the time course of any changes during detraining. Recreationally active participants in LR (aged 19 ± 2.6 years; n = 8) and SR (aged 19 ± 3.4 years; n = 8) groups undertook 8 weeks of RT and 4 weeks of detraining. Muscle size, architecture, subcutaneous fat, and strength were measured at weeks 0, 8, 10, and 12 (repeated measures). A control group (aged 23 ± 2.4 years; n = 10) was also monitored during this period. Significant (p > 0.05) posttraining differences existed in strength (on average 4 ± 2 vs. 18 ± 2%), distal anatomical cross-sectional area (59 ± 15 vs. 16 ± 10%), fascicle length (23 ± 5 vs. 10 ± 2%), and subcutaneous fat (22 ± 8 vs. 5 ± 2%), with LR exhibiting greater adaptations than SR. Detraining resulted in significant (p > 0.05) deteriorations in all muscle parameters measured in both groups, with the SR group experiencing a more rapid relative loss of postexercise increases in strength than that experienced by the LR group (p > 0.05). Greater morphological and architectural RT adaptations in the LR (owing to higher mechanical stress) result in a more significant increase in strength compared with that of the SR. The practical implications for this body of work follow that LR should be observed in RT where increased muscle strength and size are the objective, because we demonstrate here that ROM should not be compromised for greater external loading.

Muscle-mass loss augers increased morbidity and mortality in critically ill patients. Muscle-mass loss can be assessed by wide linear-array ultrasound transducers connected to cumbersome, expensive console units. Whether cheaper, hand-carried units equipped with curved-array transducers can be used as alternatives is unknown. Accordingly, our primary aim was to investigate in 15 nondisabled subjects the validity of measurements of rectus femoris cross-sectional area by using a curved-array transducer against a linear-array transducer-the reference-standard technique. In these subjects, we also determined the reliability of measurements obtained by a novice operator versus measurements obtained by an experienced operator. Lastly, the relationship between quadriceps strength and rectus area recorded by two experienced operators with a curved-array transducer was assessed in 17 patients with chronic obstructive pulmonary disease (COPD). In nondisabled subjects, the rectus cross-sectional area measured with the curved-array transducer by the novice and experienced operators was valid (intraclass correlation coefficient [ICC]: 0.98, typical percentage error [%TE]: 3.7%) and reliable (ICC: 0.79, %TE: 9.7%). In the subjects with COPD, both reliability (ICC: 0.99) and repeatability (%TE: 7.6% and 9.8%) were high. Rectus area was related to quadriceps strength in COPD for both experienced operators (coefficient of determination: 0.67 and 0.70). In conclusion, measurements of rectus femoris cross-sectional area recorded with a curved-array transducer connected to a hand-carried unit are valid, reliable, and reproducible, leading us to contend that this technique is suitable for cross-sectional and longitudinal studies.

Purpose: The purposes of this study were to define the anatomy of the anterior inferior iliac spine (AIIS) and its relation to the footprint of the rectus femoris tendon and to evaluate on the clinical outcomes after AIIS/subspine decompression., Methods: The rectus origin was dissected and detached in 11 male cadaveric hips with a mean age of 54.3 ± 14.3 years (range, 33 to 74 years). The proximal-distal and medial-lateral extent of the footprint and its relation to the AIIS and acetabular rim were evaluated, with the 12-o'clock position defined as directly lateral at the insertion of the indirect head of the rectus tendon and the 1- to 6-o'clock positions defined as anterior acetabular positions. To assess the safety and efficacy of subspine decompression for AIIS deformity, clinical correlation of a series of 163 AIIS decompressions (mean age, 27.8 years; age range, 14 to 52 years) performed from January 2011 to January 2012 was completed, and outcome scores, strength deficits, and ruptures were assessed by manual muscle testing and postoperative radiographs. All patients presented with symptomatic FAI with proximal femoral and/or acetabular deformity and type 2 (131 hips) or type 3 (32 hips) AIIS morphology as defined by Hetsroni et al., Results: The mean proximal-distal and medial-lateral distances for the rectus origin footprint were 2.2 ± 0.1 cm (range, 2.1 to 2.4 cm) and 1.6 ± 0.3 cm (range, 1.2 to 2.3 cm), respectively. There was a characteristic bare area at the anteromedial AIIS. On the clock face, the lateral margin (1-o'clock to 1:30 position) and medial margin (2-o'clock to 2:30 position) of the AIIS and the indirect head of the rectus (12 o'clock) were consistent for all specimens. In the clinical series, 163 AIIS decompressions were performed for symptomatic subspine impingement. The mean modified Harris Hip Score was 63.1 points (range, 21 to 90 points) preoperatively compared with 85.3 points (range, 37 to 100 points) at a mean follow-up of 11.1 ± 4.1 months (range, 6 to 24 months) (P < .01). Short Form 12 scores improved significantly from a mean of 70.4 (range, 34 to 93) preoperatively to a mean of 81.3 (range, 31 to 99) postoperatively (P < .01). The mean pain score on a visual analog scale also improved significantly from a mean of 4.9 (range, 0.1 to 8.6) preoperatively to a mean of 1.9 (range, 0 to 7.8) postoperatively (P < .01). The mean alpha angle improved from 61.5° (range, 35° to 90°) preoperatively to 49° (range, 35° to 63°) postoperatively on anteroposterior radiographs and from 71° (range, 45° to 90°) preoperatively to 44.3° (range, 37° to 60°) postoperatively on lateral radiographs. No short- or long-term hip flexion deficits or rectus femoris avulsions were noted with up to 2 years' follow-up., Conclusions: The origin of the rectus femoris tendon is broad on the AIIS and protective against direct head detachment with subspine decompression. This broad origin and consistent bare area anteromedially on the AIIS can be readily used by surgeons to perform a safe AIIS resection in cases of symptomatic impingement. Arthroscopic subspine decompression in addition to osteoplasty for symptomatic cam- and/or pincer-type FAI deformities can reliably improve outcome scores without significant hip flexion deficits or AIIS/rectus femoris avulsions., Clinical Relevance: The direct head of the rectus tendon has a broad insertion on the AIIS, and an area devoid of tendon provides a "safe zone" for subspine decompression in cases of symptomatic AIIS impingement., (Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

The interference effect attenuates strength and hypertrophic responses when strength and endurance training are conducted concurrently; however, the influence of training frequency on these responses remain unclear when varying ratios of concurrent strength and endurance training are performed. Therefore, the purpose of the study was to examine the strength, limb girth, and neuromuscular adaptations to varying ratios of concurrent strength and endurance training. Twenty-four men with >2 years resistance training experience completed 6 weeks of 3 days per week of (a) strength training (ST), (b) concurrent strength and endurance training ratio 3:1 (CT3), (c) concurrent strength and endurance training ratio 1:1 (CT1), or (d) no training (CON) in an isolated limb model. Assessments of maximal voluntary contraction by means of isokinetic dynamometry leg extensions (maximum voluntary suppression [MVC]), limb girth, and neuromuscular responses through electromyography (EMG) were conducted at baseline, mid-intervention, and postintervention. After training, ST and CT3 conditions elicited greater MVC increases than CT1 and CON conditions (p ≤ 0.05). Strength training resulted in significantly greater increases in limb girth than both CT1 and CON conditions (p = 0.05 and 0.004, respectively). The CT3 induced significantly greater limb girth adaptations than CON condition (p = 0.04). No effect of time or intervention was observed for EMG (p > 0.05). In conclusion, greater frequencies of endurance training performed increased the magnitude of the interference response on strength and limb girth responses after 6 weeks of 3 days a week of training. Therefore, the frequency of endurance training should remain low if the primary focus of the training intervention is strength and hypertrophy.

Background: Self-administered epinephrine is the primary out-of-hospital treatment of anaphylaxis. Intramuscular injection of epinephrine results in higher peak plasma concentration than subcutaneous injection. With the prevalence of obesity, autoinjectors may not have an adequate needle length for intramuscular injection., Objectives: To measure muscle depth and evaluate predictors of autoinjector needle length inadequacy., Methods: We performed a prospective cross-sectional study of a convenience sample of low acuity emergency department patients aged 18 to 55 years. We recorded demographic data, measured thigh circumference, and calculated body mass index (BMI). Using ultrasound, we took depth-to-muscle measurements of the vastus lateralus in a standing position, with and without gentle pressure to simulate muscle compression that occurs with correct autoinjector use. We conducted univariate analyses using χ(2) and t tests with P ≤ .05 and 95% confidence intervals. We considered the patient a potential "failure" risk if his/her muscle depth exceeded 15.9 mm (longest available epinephrine autoinjectors needle)., Results: We enrolled 120 subjects with a mean BMI of 29.2 kg/m(2). Thirty-one percent (31%) of our sample were found to be failure risks (36/116; confidence interval, 22.6%-39.5%). Women were 6.4 times more likely than men to be a failure risk (54.4% vs 5% for men failure rate; P < .001). Failures were more likely to be shorter, have a higher BMI, and have larger thigh circumference (P < .001). We did not find any statistical difference in muscle depth for race, age, or weight., Conclusion: The current epinephrine autoinjector needle length is inadequate for intramuscular injection, especially among women., (© 2013.)

The aim of this work was to study the effect of training volume on activation of satellite cells. Healthy untrained men were randomly assigned into two groups. The 3L-1UB group (n = 10) performed three-set leg exercises and single-set upper body exercises, and the 1L-3UB group (n = 11) performed single-set leg exercises and three-set upper body exercises. Both groups performed three sessions (80-90 min) per week for 11 weeks. Biopsies were taken from m. vastus lateralis and m. trapezius. The number of satellite cells, satellite cells positive for myogenin and MyoD, and the number of myonuclei were counted. Homogenized muscle was analyzed for myogenin and MyoD, and extracted ribonucleic acid (RNA) was monitored for selected growth factor transcripts. Knee extensor strength increased more in the 3L-1UB group than in the 1L-3UB group (48 ± 4% vs 29 ± 4%), whereas the strength gain in shoulder press was similar in both training groups. The number of satellite cells in m. vastus lateralis increased more in the 3L-1UB group than in the 1L-3UB group. The number of myonuclei increased similarly in both groups. The messenger RNA expression of growth factors peaked after 2 weeks of training. In conclusion, increasing training volume enhanced satellite cell numbers in the leg muscle, but not in the upper body muscle., (© 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Costameres are mechano-sensory sites of focal adhesion in the sarcolemma that provide a structural anchor for myofibrils. Their turnover is regulated by integrin-associated focal adhesion kinase (FAK). We hypothesized that changes in content of costamere components (beta 1 integrin, FAK, meta-vinculin, gamma-vinculin) with increased and reduced loading of human anti-gravity muscle would: (i) relate to changes in muscle size and molecular parameters of muscle size regulation [p70S6K, myosin heavy chain (MHC)1 and MHCIIA]; (ii) correspond to adjustments in activity and expression of FAK, and its negative regulator, FRNK; and (iii) reflect the temporal response to reduced and increased loading. Unloading induced a progressive decline in thickness of human vastus lateralis muscle after 8 and 34 days of bedrest (-4% and -14%, respectively; n = 9), contrasting the increase in muscle thickness after 10 and 27 days of resistance training (+5% and +13%; n = 6). Changes in muscle thickness were correlated with changes in cross-sectional area of type I muscle fibers (r = 0.66) and beta 1 integrin content (r = 0.76) at the mid-point of altered loading. Changes in meta-vinculin and FAK-pY397 content were correlated (r = 0.85) and differed, together with the changes of beta 1 integrin, MHCI, MHCII and p70S6K, between the mid- and end-point of resistance training. By contrast, costamere protein level changes did not differ between time points of bedrest. The findings emphasize the role of FAK-regulated costamere turnover in the load-dependent addition and removal of myofibrils, and argue for two phases of muscle remodeling with resistance training, which do not manifest at the macroscopic level., (© 2013 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.)

The purpose of this study was to examine the effects of 2 different types of protein supplementation on thigh muscle cross-sectional area (CSA), blood markers, muscular strength, endurance, and body composition after 8 weeks of low- or moderate-volume resistance training in healthy, recreationally trained, college-aged men. One hundred and six men were randomized into 5 groups: low-volume resistance training with bioenhanced whey protein (BWPLV; n = 22), moderate-volume resistance training with BWP (BWPMV; n = 20), moderate-volume resistance training with standard whey protein (SWPMV; n = 22), moderate-volume resistance training with a placebo (PLA; n = 21), or moderate-volume resistance training with no supplementation (CON; n = 21). Except for CON, all groups consumed 1 shake before and after each exercise session and one each on the nontraining day. The BWPLV, BWPMV, and SWPMV groups received approximately 20 g of whey protein per shake, whereas the BWP groups received 5 g of additional polyethylene glycosylated (PEG) leucine. Resistance training sessions were performed 3 times per week for 8 weeks. There were no interactions (p > 0.05) for muscle strength and endurance variables, body composition, muscle CSA, and safety blood markers, but the main effects for training were observed (p ≤ 0.05). However, the Albumin:Globulin ratio for SWPMV was lower (p = 0.037) than BWPLV and BWPMV. Relative protein intake (PROREL) indicated a significant interaction (p < 0.001) with no differences across groups at pre; however, BWPLV, BWPMV, and SWPMV had a greater intake than did PLA or CON at post (p < 0.001). This study indicated that 8 weeks of resistance training improved muscle performance and size similarly among groups regardless of supplementation.

Background: The autograft of choice for anterior cruciate ligament (ACL) reconstruction remains controversial. The quadriceps tendon is the least utilized and least studied of the potential autograft options., Purpose: To determine if the quadriceps tendon has the anatomic characteristics to produce a graft whose length and volume are adequate, reproducible, and predictable when compared with the other commonly used autografts., Study Design: Cross-sectional study; Level of evidence, 3., Methods: Axial proton density magnetic resonance imaging (MRI) scans of 60 skeletally mature patients (30 male and 30 female) were evaluated. Volumetric analysis of 3-dimensional models of the patellar and quadriceps tendons was performed before and after the removal of a 10 mm-wide graft from both tendons. Length, thickness, and width measurements of the quadriceps tendon were made at predetermined locations. Anthropometric data were collected, and subgroup analysis, sex analysis, and linear regression were performed., Results: The mean percentage of volume remaining after removal of a 10 mm-wide graft from the patellar tendon was 56.6%, compared with 61.3% when harvesting an 80 mm-long graft of the same width from the quadriceps tendon. The intra-articular volume of the proposed quadriceps tendon graft was 87.5% greater than that of the patellar tendon graft. The mean length of the quadriceps tendon was 73.5 ± 12.3 mm in female patients and 81.1 ± 10.6 mm in male patients. These measurements were most highly correlated with patient height. The width of the quadriceps tendon decreased as one proceeded proximally from its insertion, and the thickness of the quadriceps tendon remained relatively constant., Conclusion: The quadriceps tendon has the anatomic characteristics to produce a graft whose length and volume are both reproducible and predictable, while yielding a graft with a significantly greater intra-articular volume than a patellar tendon graft with a similar width.

This study investigated the chronology of neural and morphological adaptations to knee extensor eccentric training and their contribution to strength gains in isometric, concentric and eccentric muscle actions. 20 male healthy subjects performed a 12-week eccentric training program on an isokinetic dynamometer, and neuromuscular evaluations of knee extensors were performed every 4 weeks. After 12 training weeks, significant increases were observed for: isometric (24%), concentric (15%) and eccentric (29%) torques; isometric (29%) and eccentric (33%) electromyographic activity; muscle thickness (10%) and anatomical cross-sectional area (19%). Eccentric and isometric torques increased progressively until the end of the program. Concentric torque and muscle mass parameters increased until the eighth training week, but did not change from this point to the twelfth training week. Eccentric and isometric activation increased at 4 and 8 training weeks, respectively, while no change was found in concentric activation. These results suggest that: 1) the relative increment in concentric strength was minor and does not relate to neural effects; 2) eccentric and isometric strength gains up to 8 training weeks are explained by the increased neural activation and muscle mass, whereas the increments in the last 4 training weeks seem to be associated with other mechanisms., (© Georg Thieme Verlag KG Stuttgart · New York.)

While various factors have been assumed to affect knee joint biomechanics, few data have been reported on the function of the extensor mechanism in deep flexion of the knee. This study analyzed the patellofemoral joint contact kinematics and the ratio of the quadriceps and patellar tendon forces in living subjects when they performed a single leg lunge up to 150 deg of flexion. The data revealed that in the proximal-distal direction, the patellofemoral articular contact points were in the central one-third of the patellar cartilage. Beyond 90 deg of flexion, the contact points moved towards the medial-lateral edges of the patellar surface. At low flexion angles, the patellar tendon and quadriceps force ratio was approximately 1.0 but reduced to about 0.7 after 60 deg of knee flexion, implying that the patella tendon carries lower loads than the quadriceps. These data may be valuable for improvement of contemporary surgical treatments of diseased knees that are aimed to achieve deep knee flexion.

Nine to 12 weeks of resistance exercise training in young individuals induces quadriceps muscle (∼6%) and region-specific patellar tendon (4-6%) hypertrophy. However, 12 weeks of resistance exercise training (∼1 h total exercise time) in older individuals (60-78 years) induces quadriceps muscle hypertrophy (9%) without impacting patellar tendon size. The current study examined if a different loading paradigm using cycle exercise would promote patellar tendon hypertrophy or alter the internal tendon properties, measured with magnetic resonance imaging signal intensity, in older individuals. Nine women (70 ± 2 years) completed 12 weeks of aerobic upright cycle exercise training (∼28 h total exercise time). Aerobic exercise training increased (P < 0.05) quadriceps muscle size (11 ± 2%) and VO2max (30 ± 9%). Mean patellar tendon cross-sectional area (CSA) (2 ± 1%) and signal intensity (-1 ± 2%) were unchanged (P > 0.05) over the 12 weeks of training. Region-specific CSA was unchanged (P > 0.05) at the proximal (-1 ± 3%) and mid regions (2 ± 2%) of the tendon but tended (P = 0.069) to increase at the distal region (5 ± 3%). Region-specific signal intensity differed along the tendon but was unchanged (P > 0.05) with training. Although more studies are needed, exercise-induced patellar tendon hypertrophy, compared with skeletal muscle, appears to be attenuated in older individuals, while the loading pattern associated with aerobic exercise seems to have more impact than resistance exercise in promoting patellar tendon hypertrophy., (© 2011 John Wiley & Sons A/S.)

The aim of this study was to show the connection between structure (anatomical and histochemical) and function (muscle contraction properties) of vastus medialis obliquus (VMO) and vastus medialis longus (VML). The non-invasive tensiomyography (TMG) method was used to determine the contractile properties (contraction time; T(c)) of VML and VMO muscle, as a reflection of the ratio between the slow and fast fibers in two groups of nine young men. VML and VMO significantly (P < 0.01) differ in the proportion of type 1 (59.6: 44%) and type 2b (6.3: 15%) fibers. The VML muscle is almost entirely composed of type 1 and type 2a fibers. In many samples of this muscle no type 2b fibers were found. The proportion of slow-twitch type 1 fibers is nearly twice as high as the proportion of fast-twitch type 2a fibers. These observations indicate that VML is a slower and more fatigue-resistant muscle than VMO muscle. These characteristics correspond to the different functions of the VML, which is an extensor of the knee, and to the VMO, which maintains the stable position of the patella in the femoral groove. Our results obtained by TMG provided additional evidence that muscle fibers within the segments of VM muscle were not homogenous with regard to their contractile properties, thereby confirming the histochemical results. T(c) can be attributed to the higher percentage of slow-twitch fibers - type 1. The statistically shorter T(c) (P ≤ 0.001) of VMO (22.8 ± 4.0 ms) compared with VML (26.7 ± 4.0 ms) in our study is consistent with previously found differences in histochemical, morphological and electrophysiological data. In conclusion, the results of this study provide evidence that the VML and VMO muscles are not only anatomically and histochemically different muscles, but also functionally different biological structures., (© 2013 Anatomical Society.)

Objective: To evaluate the residual effects of fitness and whole-body vibration (WBV) training in older men 1 year after completion of the interventions., Design: A 1-year follow-up of a randomized controlled trial comparing the effects of 1 year of fitness training, including combined resistance and aerobic (R+A) training and WBV training, with a control (CON) group., Setting: University training center., Participants: Adult men (N=72) between 60 and 80 years of age. Response rate was 80%, 92%, and 90% in the R+A training (n=20), WBV training (n=23), and CON (n=29) groups, respectively., Interventions: The intervention groups exercised 3 times weekly during 1 year. The R+A training group performed a standard training program, combining resistance exercises and aerobic training, following the American College of Sports Medicine guidelines. The WBV training group performed unloaded static and dynamic leg exercises on a vibration platform. The CON group did not participate in any training program., Main Outcome Measures: Muscle volume, isometric and concentric muscle strength, muscle quality, and muscle power., Results: Both interventions had resulted in comparable increases in muscle quality characteristics. No significant changes had been found in the CON group. During the 1-year follow-up period, the R+A (-4.05%, P=.006) and WBV (-2.45%, P<.0001) training groups had lost most of their gains in muscle volume. However, isometric muscle strength was preserved in the R+A training group (+1.65%, P=.745), resulting in an increase in muscle quality (+7.97%, P=.034). In the WBV training group, muscle power decreased (-6.10%, P<.0001) but remained significantly higher than at baseline (P=.038). Except for a strong decrease in muscle power, no significant changes were found in the CON group., Conclusions: One year of R+A and/or WBV training can equally reverse the adverse effects of aging on muscle quality in older men, but their residual impact after follow-up is different., (Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength., Design: Open intervention study., Setting: Laboratory setting., Participants: Untrained individuals with chronic spinal cord injury (N=8)., Interventions: Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d., Main Outcome Measures: Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed., Results: Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training., Conclusions: These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences., (Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Pediatric normal brachial biceps (14 specimens) and quadriceps muscles (14 specimens) were studied by immunohistochemistry to quantify fiber-type, diameter and distribution, capillary density, presence of inflammatory cells (CD3, CD20, CD68) and expression of neonatal myosin and MHC class 1 proteins. Brachial biceps showed more fast-twitch fibers and lower capillary/fiber ratio than quadriceps. The mean diameter of both fiber types was smaller in biceps than quadriceps. Fast-fibers were smaller than slow-fibers, and capillary/fiber ratio was < 1.0 in both muscles. Fiber size and capillary / fiber ratio increased with age. Normal limits for infiltrating haematopoietic cells were <4 T lymphocytes, or CD68+ cells, very few B cells, < 6 neonatal myosin positive fibers, and no fibers MHC class 1 positive in one x20 field, for both muscles. The present comparison of quantitative findings between brachial biceps and quadriceps may allow standardization of the assessment of pathological changes in both pediatric muscles.

Introduction: Resistance training has been well established as an effective treatment strategy to increase skeletal muscle mass and strength in the elderly. We assessed whether dietary protein supplementation can further augment the adaptive response to prolonged resistance-type exercise training in healthy elderly men and women., Methods: Healthy elderly men (n = 31, 70 ± 1 yr) and women (n = 29, 70 ± 1 yr) were randomly assigned to a progressive, 24-wk resistance-type exercise training program with or without additional protein supplementation (15 g·d-1). Muscle hypertrophy was assessed on a whole-body Dual-energy X-ray absorptiometry (DXA), limb (computed tomography), and muscle fiber (biopsy) level. Strength was assessed regularly by 1-repetition maximum (RM) strength testing. Functional capacity was assessed with a sit-to-stand and handgrip test., Results: One-RM strength increased by 45% ± 6% versus 40% ± 3% (women) and 41% ± 4% versus 44% ± 3% (men) in the placebo versus protein group, respectively (P < 0.001), with no differences between groups. Leg muscle mass (women, 4% ± 1% vs 3% ± 1%; men, 3% ± 1% vs 3% ± 1%) and quadriceps cross-sectional area (women, 9% ± 1% vs 9% ± 1%; men, 9% ± 1% vs 10% ± 1%) increased similarly in the placebo versus protein groups (P < 0.001). Type II muscle fiber size increased over time in both placebo and protein groups (25% ± 13% vs 30% ± 9% and 23% ± 12% vs 22% ± 10% in the women and men, respectively). Sit-to-stand improved by 18% ± 2% and 19% ± 2% in women and men, respectively (P < 0.001)., Conclusion: Prolonged resistance-type exercise training increases skeletal muscle mass and strength, augments functional capacity, improves glycemia and lipidemia, and reduces blood pressure in healthy elderly men and women. Additional protein supplementation (15 g·d-1) does not further increase muscle mass, strength, and/or functional capacity.

The aim of this study was to examine the structural and mechanical properties of the patellar tendon in elite male badminton players with and without patellar tendinopathy. Seven players with unilateral patellar tendinopathy (PT group) on the lead extremity (used for forward lunge) and nine players with no current or previous patellar tendinopathy (CT group) were included. Magnetic resonance imaging was used to assess distal patellar tendon dimensions. Patellar tendon mechanical properties were assessed using simultaneous tendon force and deformation measurements. Distal tendon cross-sectional area (CSA) normalized for body weight (mm(2) /kg(2/3) ) was lower in the PT group compared with the CT group on both the non-lead extremity (6.1 ± 0.3 vs 7.4 ± 0.2, P < 0.05) and the lead extremity (6.5 ± 0.6 vs 8.4 ± 0.3, P < 0.05). Distal tendon stress was higher in the PT group compared with the CT group for both the non-lead extremity (31 ± 1 vs 27 ± 1 MPa, P < 0.05) and the lead extremity (32 ± 3 vs 21 ± 3 MPa, P < 0.01). Conclusively, the PT group had smaller distal patellar tendon CSA on both the injured (lead extremity) and the uninjured side (non-lead extremity) compared with the CT group. Subsequently, the smaller CSA yielded a greater distal patellar tendon stress in the PT group. Therefore, a small tendon CSA may predispose to the development of tendinopathy., (© 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.)

Purpose: The aim of this study was to investigate the attachment of the medial patellofemoral ligament (MPFL) using cadaver specimens and establish an anatomic basis for optimal MPFL reconstruction to achieve better patella stability., Methods: Sixteen knees of eight cadavers were used in this study. The relationship of the MPFL with quadriceps muscles was investigated from outside after removal of the distal part of the vastus medialis and the rectus femoris and then evaluated from intra-articular side after release of lateral margin of the vastus lateralis muscle, patella and patella tendon., Results: The proximal fibres of MPFL were mainly attached to the vastus intermedius tendon, without tight adhesion to the vastus medialis. The distal fibres of MPFL were interdigitated with the deep layer of the medial retinaculum that was attached to the medial margin of the patella tendon., Conclusion: These findings imply that MPFL, which was directly attached to the vastus intermedius and patella and indirectly continued to the patella tendon, could keep pulling them medially as one unit and consequently make the patella move smoothly on the trochlea during whole movement of the knee. Clinically, dysfunction of both proximal and distal MPFL fibres should be considered in the diagnosis and treatment of patella instability after traumatic patella dislocation. MPFL reconstruction with both fibres has a possibility to lead ideal function of MPFL and better instability of the patella.

Purpose: The quadriceps angle (Q-angle) represents the angle between the vector of action of the quadriceps and the patellar tendon. An increased Q-angle has been associated with an increased risk of patellar instability, although there is disagreement on its reliability and validity as it is affected by the position of the limb and contraction of the quadriceps. Tibial tuberosity-trochlear groove distance (TT-TG) is ascertained by axial CT scanning, with an increased value associated with patellar instability. This study aimed to determine whether the Q-angle correlates with the TT-TG distance in patients with patellar instability., Methods: Q-angles were measured in 34 knees that had previously undergone CT scanning for assessment of patellar instability. Measurements were made with the patient supine, the knee extended and the lower limbs in neutral rotation with the quadriceps relaxed and contracted. TT-TG distance was measured on CT scanning in an identical position., Results: Of the 34 knees measured, 24 had symptoms of patellar instability, and 10 were normal. A significant negative correlation between relaxed Q-angle and TT-TG in all knees was demonstrated (p = 0.028). In symptomatic knees, contracted Q-angle also demonstrated a significant negative correlation with TT-TG (p = 0.037)., Conclusions: If TT-TG distance is regarded as the gold standard measurement, Q-angle is not a reliable indicator of patellar instability. There is a clear need to develop methods to more fully characterise the knee and factors contributing to patellar instability., Level of Evidence: II.

The purpose of this study was to evaluate motor unit recruitment in the quadriceps femoris (QF) after anterior cruciate ligament (ACL) rupture and repair. Subjects included 24 patients at ≥ 18 months after ACL reconstruction and 22 control subjects with no history of knee injury. A series of cross-sectional magnetic resonance images were obtained to compare the QF of patients' injured side with that of their uninjured sides and that of uninjured control subjects. Muscle torque per muscle volume was calculated as isokinetic peak torque divided by QF muscle volume (cm(3)). The mean muscle torque per unit volume of the injured side of patients was not significantly different from that of the uninjured side or control subjects (one-way ANOVA) Results of the present study were contrary to the results of a previous study that evaluated patients at ≤ 12 months after ACL reconstruction. The present study found that high-threshold motor unit recruitment was restored at ≥ 18 months after ACL reconstruction. Thus, clinicians must develop techniques that increase the recruitment of high-threshold motor units in the QF from the period immediately after the injury until approximately 18 months after ACL reconstruction., (© 2011 John Wiley & Sons A/S.)

Purpose: The purpose of this study was to evaluate the anatomical structure of the quadriceps tendon in detail for use as an anterior cruciate ligament (ACL) graft tendon., Materials and Methods: Sixteen cadaveric knees with an average age of 78.8 were used. After careful dissection of skin and fascia, the muscle structure of each quadriceps was evaluated. In particular, the rectus femoris (RF) tendon was measured at its widest and narrowest width, the distance between widest or narrowest point and the proximal end of the patella, and the length., Results: The quadriceps tendon consisted of three layers. At the surface layer, the RF tendon existed mostly independently. The middle layer consisted of the vastus lateralis (VL) and medialis (VM) tendons. The deep layer consisted of the vastus intermedius (VI) tendon. The VL and VI tendons overlapped and were firmly connected, constituting the strength and size of the quadriceps. The narrowest width of the RF was 15.3 mm, and the narrowest point existed 4.8 mm proximal to the upper end of the patella. The average length of the RF was 27.3 cm., Conclusion: If the RF tendon only is used as an ACL graft, surgeons should be cautious of the fact that the narrowest point of the RF tendon is located close to the patella. The entire quadriceps tendon is big enough to be used as an ACL graft. However, since the direction of the VL and VI tendons is different, the suitability of the quadriceps tendon as an ACL graft is questionable.

Purpose: Although physical therapy is known to be effective in treating patellofemoral pain (PFP), there is considerable individual variation in the treatment response. It is unclear why some patients benefit from a specific treatment while others do not experience improvement. This study, using a prospective study design, aims to identify factors that could predict the short-term functional outcome and account for the variation frequently seen in the outcome after conservative treatment of PFP., Methods: Thirty-six patients (20 female and 16 male with a mean age of 23.8 ± 6.7 yr) followed a physical therapy rehabilitation program of 7 wk. Before this treatment, all patients were evaluated on subjective symptoms (pain on visual analog scales in millimeters) and functional performance (step test expressed as highest level, single-legged hop test in centimeters, and triple-hop test in centimeters). The concentric and eccentric knee extensor strength at 60°.s(-1) and 240°.s(-1) (N.m) were measured as well as the quadriceps muscle size by calculating the cross-sectional area (cm(2)) with magnetic resonance imaging. The success of the treatment was evaluated by the functional Kujala anterior knee pain scale. A linear regression model was used to identify predisposing factors for the functional outcome., Results: The total quadriceps cross-sectional area (P = 0.010), the eccentric average peak torque at 60°.s(-1) (P = 0.015), and the frequency of pain at baseline (P = 0.012) have been indicated as predisposing variables in the short-term functional outcome after a physical therapy rehabilitation program for PFP (adjusted R(2) = 0.46)., Conclusion: Patients with a greater quadriceps muscle size, lower eccentric knee strength, and less pain have a better short-term functional outcome after conservative treatment for PFP.

Objective: To investigate the anatomic features of the perforating branch flap of the medial vastus muscle, so as to provide a new perforating branch flap for repairing the soft tissue defect., Methods: Six fresh donated lower limb specimens underwent an intra-arterial injection of a lead oxide and lactoprene preparation. The integument of the thigh was dissected to observe the origin, course, size, and location of the perforating branch of the medial vastus muscle by angiography and photography. Based on the anatomic study, the free perforating branch flaps of the medial vastus muscle (14 cm x 6 cm to 20 cm x 5 cm) were used to repair skin and soft tissue defects (8 cm x 6 cm to 12 cm x 8 cm) of the feet in 4 patients between June 2009 and August 2011., Results: The artery of the medial vastus was sent out constantly from the femoral artery, and then descended in the vastus muscle to lateral patella where it anastomosed with the terminal branches of lateral femoral circumflex artery to form prepatellar vascular network. The artery of the medial vastus sent out 3-5 musculocutaneous perforating branches into the deep fascia and then extended superficially to the overlying skin. Four flaps survived after surgery; wounds at the donor site and recipient site healed by first intention. After follow-up of 6-12 months, the flaps had good appearance and texture. All ankles had normal movement range of plantarflexion and dorsiflexion., Conclusion: The free perforating branch flaps of the medial vastus muscle can be harvested easily, and have the advantage of good texture and abundant donor site.

Non-human primates (NHP) represent an emerging animal model for the study of physical function, and provide opportunities for exploration of relationships of muscle biomolecular changes with age. One such primate model, the African green vervet monkey, has been used extensively in biomedical research but little is known regarding skeletal muscle composition, expression of myosin heavy chain (MHC) isoforms, and changes with age. In the present study we examined the effects of age on vastus lateralis (VL) muscle fiber-type composition, fiber cross-sectional area (CSA), and MHC isoforms expressed in 4 young and 4 older adult vervet monkeys. Proteomics analysis, using a human and nonhuman primate protein database, showed five MHC isoforms (I, IIA, IIX, IIB, and IIB') expressed in female vervet VL muscle, which matched the human MHC isoforms. Fast type II fibers predominated and no pure type IIB or IIB' containing fibers were detected. Hybrid fibers containing IIB/IIB' MHC decreased in the old vervets. The CSA of both type I and type II fibers was significantly smaller in older vervet while type IIA fibers showed the most severity of atrophy. The decrease of fast MHC and atrophy of muscle fiber with aging recapitulate observations in human VL muscle. These findings, along with its homology of MHC between the vervet and human suggested that the vervet monkey may be a suitable preclinical model for understanding the cellular and molecular basis of sarcopenia and for developing new interventions to ameliorate the impact of disorders that affect skeletal muscle structure and function., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We investigated whether there were regional differences in the quadriceps enthesis and the patella bone structure that could suggest unequal force transmission to the patella. Quadriceps tendon enthesis was removed by cutting the patellae transversally in the middle and the quadriceps tendon approximately 1 cm from the bone. Tissues were post-fixed, decalcified, dehydrated through and embedded in paraffin wax. Serial longitudinal sections were cut, mounted on glass slides at 1-mm intervals and slides were stained. Trabecular architecture was analysed from digital images taken from the histological slides, and regional differences at the enthesis in the thickness of the uncalcified fibrocartilage and the cortical zone of calcified tissue (calcified cartilage and lamellar bone) were evaluated. At the quadriceps enthesis, the thickness of the cortical zone of calcified tissue was significantly greater in the central part of the enthesis than medially and laterally. The trabeculae were thicker in the central and lateral parts compared with the medial region. Similarly, the zone of uncalcified fibrocartilage was thicker laterally and centrally than medially. Bone structure and the thickness of uncalcified fibrocartilage presented a similarity between the centre and the lateral parts; however, the medial side was different. We suggest that the mechanical stress at the proximal quadriceps tendon enthesis is higher laterally and centrally compared with medially. This could induce a lateral patellar translation, which is potentially a risk factor for knee osteoarthritis., (© 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.)

The skeletal muscle system can adapt to an external stimulus from either physiological or pathological conditions. This plasticity is measured by imaging techniques such as magnetic resonance imaging or ultrasound. The anatomical cross-sectional area of a muscle is one of the muscle architecture parameters that relates to the maximum muscle strength. The aim of this study was to determine the reliability of anatomical cross-sectional area rectus femoris measurements, obtained by ultrasound, with two different protocols. Acquisition of four anatomical cross-sectional area images of the right rectus femoris in two distinct regions (15 cm above the patella and 50% of the thigh length) was performed in 2 days, from a group of 15 young healthy subjects. The cross-sectional area of each image was measured five times. The reliability of the anatomical cross-sectional area measures was determined by the coefficient of variation (CV), intraclass correlation coefficient (ICC) and typical error of measurement (TEM). In each protocol, there were no significant differences between the means of anatomical cross-sectional area in measurements, images and days (P>0·05). The CVs were 8·53% and 8·9%, the ICCs 0·88 and 0·87 and the TEMs 65·59 and 94·25 between the 2 days in the regions of 15 cm and 50% of the thigh length, respectively. The average values of the cross-sectional area at 50% of the thigh length were significantly higher than those for at 15 cm above the patella (P<0·001). The measurement of rectus femoris anatomical cross-sectional area by ultrasound proved reliable., (© 2012 The Authors. Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Objectives: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra- and interobserver reliability, potential sources of error, and the effect of Q angle variation., Study Design: Cadaveric radiographic study and computer modeling., Animals: Pelvic limbs from red foxes (Vulpes vulpes)., Methods: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F(MEDIAL)) was calculated., Results: The HD position yielded significantly (P < .001) more medial Q angles than the WL position. No significant difference was observed between Q1 and Q2, but Bland-Altman plots indicated they were not equivalent. Intra- and interobserver agreement was substantial. Q2 errors were inherently greater than Q1: the mid-point and tibial tuberosity are the most important sources of Q angle variability. Increasing Q angles significantly increased the exerted F(MEDIAL) (P < .0001, gradient 1.7%)., Conclusions: Measurements are reliable, but Q2 is more prone to error than Q1, and the 2 measurement techniques are not interchangeable. Positional errors must be kept below 1.3 mm (Q1) or 0.8 mm (Q2)., (© Copyright 2012 by The American College of Veterinary Surgeons.)

The purpose of this study was to compare the component characteristics of thigh muscle volume in Japanese young and older men. The subjects in both young (YM, n = 15) and older (OM, n = 13) men were physically active (performed aerobic-type exercise 1-3 times per week), but none of the subjects had regularly participated in resistance training for a minimum of 3 years prior to the study. Contiguous transverse magnetic resonance imaging (1.5-T scanner) images were obtained from the thigh, and total and individual (quadriceps, hamstrings and adductors) muscle volumes were calculated by multiplying the muscle cross-sectional area (CSA) by slice thickness and the total number of slices. Muscle length and average muscle CSA (muscle volume divided by muscle length) were determined for each muscle. Maximum voluntary isometric (MVC) knee extension and flexion strength were measured, and muscle quality was defined as MVC per unit average muscle CSA (MVC/CSA). Quadriceps muscle volume and average CSA were, respectively, 20% and 16% lower (P < 0.05) in the OM than in the YM, while hamstrings and adductors muscle volumes and average CSA were similar in both groups. Knee extension and flexion MVC were lower (P < 0.05) in the OM than in the YM. Knee extensor MVC/CSA was similar in the two groups, while knee flexor MVC/CSA was lower (P < 0.05) in the OM than in the YM. Our results suggest that age-related thigh muscle volume loss is muscle specific, in that greater quadriceps muscle loss was found in the older group., (© 2011 The Authors. Clinical Physiology and Functional Imaging © 2011 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Background: Recently, ultrasound-guided saphenous nerve blocks within and distal to the adductor canal have shown success. However, a potential side effect is an unintentional block of branches of the nerve to the vastus medialis resulting in undesired motor weakness., Methods: We dissected 40 embalmed cadaver thighs to determine the course and relation of the saphenous nerve to the nerve to the vastus medialis. Measurements were taken between various landmarks, and descriptive statistics were used to present the collected data., Results: In 72.5% of specimens, the most distal visible branch of the nerve to the vastus medialis pierced the muscle proximal to the site where the saphenous nerve crosses the anterior surface of the superficial femoral artery to become medial to the vessel., Conclusion: Knowledge of this anatomy may help establish a safe region in preventing motor blockade when performing saphenous nerve blocks., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)

Complex training (CT; alternating between heavy and lighter load resistance exercises with similar movement patterns within an exercise session) is a form of training that may potentially bring about a state of postactivation potentiation, resulting in increased dynamic power (Pmax) and rate of force development during the lighter load exercise. Such a method may be more effective than either modality, independently for developing strength. The purpose of this research was to compare the effects of resistance training (RT), plyometric training (PT), and CT on lower body strength and anthropometrics. Thirty recreationally trained college-aged men were trained using 1 of 3 methods: resistance, plyometric, or complex twice weekly for 6 weeks. The participants were tested pre, mid, and post to assess back squat strength, Romanian dead lift (RDL) strength, standing calf raise (SCR) strength, quadriceps girth, triceps surae girth, body mass, and body fat percentage. Diet was not controlled during this study. Statistical measures revealed a significant increase for squat strength (p = 0.000), RDL strength (p = 0.000), and SCR strength (p = 0.000) for all groups pre to post, with no differences between groups. There was also a main effect for time for girth measures of the quadriceps muscle group (p = 0.001), the triceps surae muscle group (p = 0.001), and body mass (p = 0.001; post hoc revealed no significant difference). There were main effects for time and group × time interactions for fat-free mass % (RT: p = 0.031; PT: p = 0.000). The results suggest that CT mirrors benefits seen with traditional RT or PT. Moreover, CT revealed no decrement in strength and anthropometric values and appears to be a viable training modality.

Fascicle angle (FA) is suggested to increase as a result of fiber hypertrophy and furthermore to serve as the explanatory link in the discrepancy in the relative adaptations in the anatomical cross-sectional area (CSA) and fiber CSA after resistance training (RT). In contrast to RT, the effects of endurance training on FA are unclear. The purpose of this study was therefore to investigate and compare the longitudinal effects of either progressive endurance training (END, n = 7) or RT (n = 7) in young untrained men on FA, anatomical CSA, and fiber CSA. Muscle morphological measures included the assessment of vastus lateralis FA obtained by ultrasonography and anatomical CSA by magnetic resonance imaging of the thigh and fiber CSA deduced from histochemical analyses of biopsy samples from m. vastus lateralis. Functional performance measures included VO2max and maximal voluntary contraction (MVC). The RT produced increases in FA by 23 ± 8% (p < 0.01), anatomical CSA of the knee extensor muscles by 9 ± 3% (p = 0.001), and fiber CSA by 19 ± 7% (p < 0.05). RT increased knee extensor MVC by 20 ± 5% (p < 0.001). END increased VO2max by 10 ± 2% but did not evoke changes in FA, anatomical CSA, or in fiber CSA. In conclusion, the morphological changes induced by 10 weeks of RT support that FA does indeed serve as the explanatory link in the observed discrepancy between the changes in anatomical and fiber CSA. Contrarily, 10 weeks of endurance training did not induce changes in FA, but the lack of morphological changes from END indirectly support the fact that fiber hypertrophy and FA are interrelated.

The motor nerve of the bi-articular rectus femoris muscle is generally split from the femoral nerve trunk into two sub-branches just before it reaches the distal and proximal regions of the muscle. In this study, we examined whether the regional difference in muscle activities exists within the human rectus femoris muscle during maximal voluntary isometric contractions of knee extension and hip flexion. Surface electromyographic signals were recorded from the distal, middle, and proximal regions. In addition, twitch responses were evoked by stimulating the femoral nerve with supramaximal intensity. The root mean square value of electromyographic amplitude during each voluntary task was normalized to the maximal compound muscle action potential amplitude (M-wave) for each region. The electromyographic amplitudes were significantly smaller during hip flexion than during knee extension task for all regions. There was no significant difference in the normalized electromyographic amplitude during knee extension among regions within the rectus femoris muscle, whereas those were significantly smaller in the distal than in the middle and proximal regions during hip flexion task. These results indicate that the bi-articular rectus femoris muscle is differentially controlled along the longitudinal direction and that in particular the distal region of the muscle cannot be fully activated during hip flexion.

Acute strength exercise elicits a transient oxidative stress, but the factors underlying the magnitude of this response remain unknown. The purpose of this investigation was to determine whether muscle-fiber type relates to the magnitude of blood oxidative stress after eccentric muscle activity. Eleven college-age men performed 3 sets of 50 eccentric knee-extensions. Blood samples taken pre-, post-, and 24, 48, 72, and 96 hr postexercise were assayed for comparison of muscle damage and oxidative-stress biomarkers including protein carbonyls (PCs). Vastus lateralis muscle biopsies were assayed for relative percentage of slow- and fast-twitch muscle fibers. There was a mixed fiber composition (Type I = 39.6% ± 4.5%, Type IIa = 35.7% ± 3.5%, Type IIx = 24.8% ± 3.8%; p = .366). PCs were elevated 24, 48, and 72 hr (p = .032) postexercise, with a peak response of 126% (p = .012) above baseline, whereas other oxidative-stress biomarkers were unchanged. There are correlations between Type II muscle-fiber type and postexercise PC. Further study is needed to understand the mechanisms responsible for the observed fast-twitch muscle-fiber oxidative-stress relationship.

The purpose of this study was to investigate the effect of blood flow-restricted training (BFRT) on jump performance in relation to changes in muscle strength. Seventeen untrained young men were assigned into either BFRT or normal training (NORT) groups and performed low-intensity [30-40% of one-repetition maximum (1RM)] resistance exercise (horizontal squat, 3-4 sets × 15-30 repetitions) twice a week for 10 weeks. The BFRT performed the exercise with their proximal thighs compressed by air-pressure cuffs for the purpose of blood flow restriction. Squat 1RM, muscle cross-sectional area (CSA) of quadriceps femoris, and countermovement jump (CMJ) height were measured before and after the 10-wk training period. Squat 1RM increased greater in BFRT than in NORT (19.3% vs. 9.7%, P < 0.01). Although the CSA increase was independent of groups, it tended to be larger in BFRT than in NORT (8.3% vs. 2.9%, P = 0.094). On the other hand, CMJ height did not change after the training (P = 0.51). In conclusion, the present study showed that BFRT induced muscle hypertrophy and strength increase, whereas it did not increase CMJ height in previously untrained young men. It is suggested that BFRT is ineffective in improving jump performance.

Introduction: The purposes of this study were to: (1) compare the power output-related patterns of absolute and normalized mechanomyographic (MMG) amplitude and mean power frequency (MPF) signals across the innervation zone (IZ) during incremental cycle ergometry; and (2) examine the influence of the IZ on the mean MMG amplitude and MPF values., Methods: Ten men performed incremental cycle ergometry tests to exhaustion. Surface MMG signals were recorded simultaneously from accelerometer arrangements placed on the vastus medialis over the IZ and proximal and distal to the IZ., Results: The results of polynomial regression indicate that the best-fit model for each site was consistent for each subject for MMG amplitude, but not for MMG MPF. Two-way analyses of variance (ANOVAs) revealed no site × power output interaction (P > 0.05) for absolute and normalized MMG amplitude and MPF values., Conclusion: Our findings demonstrate that the IZ does not influence the MMG signal during dynamic exercise., (Copyright © 2011 Wiley Periodicals, Inc.)

Objectives: The purpose of this study was to investigate the contributions of functional and morphological factors in the recovery of the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction., Methods: Nine subjects (31.3±5.8 years) underwent eccentric exercise sessions twice a week for 12 weeks. Quadriceps muscle function was evaluated using an isokinetic dynamometer (isometric and eccentric peak torque) and electromyography (RMS). Morphological changes were measured using magnetic resonance imaging., Results: The initial evaluation showed a significant deficit in knee extensor torque in the involved limb and significant muscle atrophy along the length of the quadriceps. EMG activity was lower in all tested situations. Eccentric training significantly increased isokinetic torque (from 199±51 to 240±63, p<0.05, respectively) and quadriceps area, with the greatest hypertrophy in the proximal thigh region (from 169±27 to 189±25.8 cm², p<0.01). The EMG activity of vastus medialis increased after the first six weeks of eccentric training. The increased extensor torque was correlated with quadriceps cross-sectional area (r=0.81, p<0.01) and EMG activity (r=0.69, p<0.05). After twelve weeks of training, there was a correlation only between torque and cross-sectional area (r=0.78, p<0.01)., Conclusions: 1) eccentric training proved to be a potent resource for the quadriceps recovery, both morphologically and functionally, 2) the contributions of functional and morphological factors varied according to the length of training.

Decreased muscle damage is reported as an advantage of minimally invasive surgical (MIS) approaches in total knee arthroplasty (TKA). The purpose of this study was to evaluate the anatomy of vastus medialis obliquus (VMO) tendon at its patellar insertion as well as to determine the amount and location of muscle damage comparing traditional subvastus approach and optimized subvastus approach. TKAs were performed in ten human cadavers (20 knees). In each specimen, one knee underwent the traditional subvastus approach and the contralateral knee the optimized subvastus approach. The risk of tearing and damaging the VMO muscle during the traditional subvastus approach is significantly higher (70% of the cases) compared to the optimized technique (30%). The amount of damage to the VMO muscle using the traditional subvastus approach was: 80% of the muscle's width in two cases, 60% in three cases, and 30% in two. The damage created by the optimized subvastus approach occurred along the edge of the tendon and the first fibers of the VMO muscle close to the muscle-tendon junction (less than 20% of muscle's width). Clinical studies are needed to determine the functional implications of these findings., (Copyright © 2010 Elsevier B.V. All rights reserved.)

During exercise involving a small muscle mass, peak oxygen uptake is thought to be limited by peripheral factors, such as the degree of oxygen extraction from the blood and/or mitochondrial oxidative capacity. Previously, the maximal activity of the Krebs cycle enzyme oxoglutarate dehydrogenase has been shown to provide a quantitative measure of maximal oxidative metabolism, but it is not known whether the increase in this activity after a period of training reflects the elevation in peak oxygen consumption. Fourteen subjects performed one-legged knee extension exercise for 5-7 weeks, while the other leg remained untrained. Thereafter, the peak oxygen uptake by the quadriceps muscle was determined for both legs, and muscle biopsies were taken for assays of maximal enzyme activities (at 25°C). The peak oxygen uptake was 26% higher in the trained than in the untrained muscle (395 vs. 315 ml min(-1) kg(-1), respectively; P<0.01). The maximal activities of the Krebs cycle enzymes in the trained and untrained muscle were as follows: citrate synthase, 22.4 vs. 18.2 μmol min(-1) g(-1) (23%, P<0.05); oxoglutarate dehydrogenase, 1.88 vs. 1.54 μmol min(-1) g(-1) (22%, P<0.05); and succinate dehydrogenase, 3.88 vs. 3.28 μmol min(-1) g(-1) (18%, P<0.05). The difference between the trained and untrained muscles with respect to peak oxygen uptake (80 ml min(-1) kg(-1)) corresponded to a flux through the Krebs cycle of 1.05 μmol min(-1) g(-1), and the corresponding difference in oxoglutarate dehydrogenase activity (at 38°C) was 0.83 μmol min(-1) g(-1). These parallel increases suggest that there is no excess mitochondrial capacity during maximal exercise with a small muscle mass.

Functionally, the knee comprises 2 articulations-the patellofemoral and tibiofemoral. Stability of the joint is governed by a combination of static ligaments, dynamic muscular forces, meniscocapsular aponeurosis, bony topography, and joint load. The surgeon is ill equipped to undertake surgical treatment of a dislocated knee without a sound footing in the anatomic complexities of this joint. We review the normal anatomy of the knee, emphasizing connective tissue structures and common injury patterns.

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8±2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.