Mitochondrial abnormalities are more frequent in muscles undergoing sarcopenia.

The hypothesis that the accumulation of electron transport system (ETS) abnormalities and sarcopenia are linked was investigated. Vastus lateralis, soleus, and adductor longus muscles were studied in 5-, 18-, and 36-mo-old male Fischer 344 x Brown Norway F(1) hybrid rats. A significant decrease in soleus and vastus lateralis muscle mass was observed with age. Adductor longus was resistant to muscle mass loss. Multiple serial sections were analyzed for the activities of cytochrome-c oxidase (COX) and succinate dehydrogenase (SDH). The number of fibers exhibiting a COX(-)/SDH(++) phenotype increased with age in both vastus lateralis and soleus muscles. No ETS-abnormal fibers were identified in adductor longus at any age. Cross-sectional area of ETS-abnormal fibers decreased in the abnormal region (region displaying COX(-)/SDH(++) phenotype), whereas control fibers did not. The vastus lateralis muscle, which undergoes a high degree of sarcopenia, exhibited more ETS abnormalities and associated fiber loss than the soleus and adductor longus muscles, which are more resistant to sarcopenia, suggesting a direct association between ETS abnormalities and fiber loss.     

Fumarase activity in skeletal muscle of man

Soluble extracts of human skeletal muscle have a fumarase activity of 31.2 +/- 7.27 (M. vastus lateralis quadricipitis) or 30.9 +/- 8.0 U/g wet weight at 37 degrees C (M. deltoideus). The distribution of activities in the 36 muscle samples studies is not gaussian. There is a significant correlation between the activities of citrate synthase and fumarase (r = + 0.881; p less than 0.001) in all investigated muscles, excepting M. vastus lateralis quadricipitis.     

Sprint performance is related to muscle fascicle length in male 100-m sprinters.

The purpose of this study was to investigate the relationship between muscle fascicle length and sprint running performance in 37 male 100-m sprinters. The sample was divided into two performance groups by the personal-best 100-m time: 10.00-10.90 s (S10; n = 22) and 11.00-11.70 s (S11; n = 15). Muscle thickness and fascicle pennation angle of the vastus lateralis and gastrocnemius medialis and lateralis muscles were measured by B-mode ultrasonography, and fascicle length was estimated. Standing height, body weight, and leg length were similar between groups. Muscle thickness was similar between groups for vastus lateralis and gastrocnemius medialis, but S10 had a significantly greater gastrocnemius lateralis muscle thickness. S10 also had a greater muscle thickness in the upper portion of the thigh, which, given similar limb lengths, demonstrates an altered "muscle shape." Pennation angle was always less in S10 than in S11. In all muscles, S10 had significantly greater fascicle length than did S11, which significantly correlated with 100-m best performance (r values from -0.40 to -0.57). It is concluded that longer fascicle length is associated with greater sprinting performance.     

Cellularity of organs in mature rams of different breeds

The relative importance of cell number and cell size in determining the mass of 16 organs and tissues in mature rams of six different breeds was studied through estimation of organ deoxyribonucleic acid (DNA) content. The mean fleece-free empty body weight (FFEBW) ranged from 54.6 +/- 0.3 kg for Camden Park Merinos to 76.7 +/- 1.6 kg for Strong Wool Merinos. For all organs, mass increased with FFEBW, but the relationship was significant across all sheep for only eight organs (blood, kidney, liver, abomasum, vastus lateralis muscle, skin, perirenal fat and triceps muscle). There were significant differences between breeds in the mass of 11 organs. With four (heart, rumen reticulum, small intestine and testicular fat) this difference was independent of breed differences in FFEBW, whereas with another four (kidney, abomasum, vastus lateralis muscle and skin), it was closely related to FFEBW. Breed differences in the mass of the remaining three organs (blood, liver and perirenal fat) were partly related to FFEBW and partly breed specific. Blood mass increased with FFEBW across all animals, but, within a breed, it declined as FFEBW increased. The increase in the mass of perirenal fat with FFEBW was significantly greater within a breed than between breeds. Cell number increased significantly with the mass of all organs except blood and brain. There were between-breed differences in the number of cells in seven organs (liver, heart, rumen reticulum, abomasum, small intestine, vastus lateralis muscle and skin), which, except for heart, were attributable to between-breed differences in organ mass. With heart, the increase in cell number with organ mass within a breed was greater than across all breeds. Cell size was significantly related to organ mass only with vastus lateralis muscle, spleen, perirenal fat and liver. The relationship for vastus lateralis muscle and spleen was negative, indicating that cells were smaller in larger organs. There were differences between breeds in cell size for heart, vastus lateralis and triceps muscles. These differences for heart and triceps muscle were breed specific, whereas for vastus lateralis muscle it was attributed to breed differences in organ weight. There was a 30-fold range in mean cell size across organs, with adipose tissue having the largest cells, muscle tissue intermediate and visceral tissues the smallest. In general, organ mass is positively related to FFEBW. Cell number, not cell size, is largely responsible for differences in organ mass between mature sheep of different breeds.     

Anterolateral thigh flap donor-site complications and morbidity

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.     

Inflammatory cells and apoptosis in respiratory and limb muscles of patients with COPD

Discrepancies exist regarding the involvement of cellular inflammation and apoptosis in the muscle dysfunction of chronic obstructive pulmonary disease (COPD) patients with preserved body composition. We explored whether levels of inflammatory cells and apoptosis were increased in both respiratory and limb muscles of COPD patients without nutritional abnormalities. In the vastus lateralis, external intercostals, and diaphragms of severe and moderate COPD patients with normal body composition, and in healthy subjects, intramuscular leukocytes and macrophage levels were determined (immunohistochemistry). Muscle structure was also evaluated. In the diaphragm and vastus lateralis of severe and moderate COPD patients and controls, apoptotic nuclei were explored using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, electron microscopy, and caspase-3 expression. In COPD patients compared with controls, diaphragm and intercostal levels of inflammatory cells were extremely low and not significantly different. However, in the vastus lateralis of the severe patients, inflammatory cell counts, although also very low, were significantly greater. In those patients, TUNEL-positive nuclei levels were also significantly greater in diaphragms and vastus lateralis. A significant inverse relationship was found between quadriceps TUNEL-positive nuclei levels and muscle force. Ultrastructural apoptotic nuclei revealed no differences in respiratory or limb muscles between COPD patients and controls. Muscle caspase-3 expression did not differ between patients and controls. In severe COPD patients with preserved body composition, while increased apoptotic nuclei seems to be a contributor to their muscle dysfunction, cellular inflammation does not. The increased numbers of TUNEL-positive nuclei in their muscles suggest that they may also be exposed to a continuous repair/remodeling process.     

Effects of Denervation and Simple Disuse on Rates of Oxidation and on Activities of Four Mitochondrial Enzymes in Type I Muscle

To differentiate the effect of muscle contractile activity from that of motor nerve on oxidative processes in type I muscle, oxidative processes were studied in muscle after immobilization and after denervation. The two processes led to similar atrophy of muscle weight and of the mean diameter of muscle fibers. Disuse of soleus muscle (type I) did not affect rates of oxidation of 14C-labeled substrates although these were reduced by disuse of the vastus lateralis (type II). Disuse of the soleus did not affect activities of several mitochondrial enzymes assayed by histochemical or biochemical methods. However, denervation of the soleus did lead to a fall in metabolic rates and enzyme activities. The activity of 3-hydroxybutyrate dehydrogenase fell more than did the activities of succinic dehydrogenase, lipoamide dehydrogenase, or cytochrome-c oxidase in both homogenates and in mitochondrial fractions. These results suggest nerve may regulate mitochondrial enzymes in type I muscle. The mechanism appears to be different from that which regulates oxidative processes in type II muscle.     

Effects of endurance training on a mitochondrial reticulum in limb skeletal muscle

High voltage electron microscopy at 1500 kV, was used to examine the effects of endurance training on mitochondrial morphology in rat skeletal muscle. The soleus, deep portions of the vastus lateralis, and superficial portions of the vastus lateralis muscles were examined to represent slow-twitch-oxidative, fast-twitch-oxidative-glycolytic, and fast-twitch-glycolytic skeletal muscle fiber types, respectively. Muscle samples were removed from endurance trained and untrained control female Wistar rats (n = 6, each group). Tissues were fixed using standard electron microscopic techniques and sectioned transversely with respect to muscle fiber orientation to approximately, 0.5 micron thickness. The sections were stained on grids with uranyl acetate and Reynolds' lead citrate. Results confirmed the presence of a mitochondrial reticulum in all three skeletal muscle fiber types of both groups. Stereologic analyses indicated volume densities of intermyofibrillar mitochondria increased significantly (P less than 0.05) with endurance training in the three skeletal muscle fiber types. Surface-to-volume ratio of mitochondria was significantly decreased (P less than 0.05) after training only in the deep portion of the vastus lateralis muscle. It was concluded that the mitochondria in mammalian limb skeletal muscle are a reticulum which adapts to endurance training by proliferating.     

Comparative effects of hindlimb suspension and exercise on skeletal muscle myosin isozymes in rats

The purpose of this study was to ascertain the time course of changes, whilst suspending the hindlimb and physical exercise training, of myosin light chain (LC) isoform expression in rat soleus and vastus lateralis muscles. Two groups of six rats were suspended by their tails for 1 or 2 weeks, two other groups of ten rats each were subjected to exercise training on a treadmill for 9 weeks, one to an endurance training programme (1-h running at 20 m.min-1 5 days.week-1), and the other to a sprint programme (30-s bouts of running at 60 m.min-1 with rest periods of 5 min). At the end of these experimental procedures, soleus and vastus lateralis superficialis muscles were removed for myosin LC isoform determination by two-dimensional gel electrophoresis. Hindlimb suspension for 2 weeks significantly increased the proportion of fast myosin LC and decreased slow myosin LC expression in the soleus muscle. The pattern of myosin LC was unchanged in the vastus lateralis muscle. Sprint training or endurance training for 9 weeks increased the percentage of slow myosin LC in vastus lateralis muscle, whereas soleus muscle myosin LC was not modified. These data indicate that hindlimb suspension influences myosin LC expression in postural muscle, whereas physical training acts essentially on phasic muscle. There were no differences in myosin LC observed under the influence of sprint- or endurance-training programme.     

Biofeedback as a means to alter electromyographic activity in a total knee replacement patient

This paper presents a single case controlled study of a 75-year-old male having bilateral total knee replacement. Baseline EMG recordings demonstrated differential levels of vastus medialis and vastus lateralis muscle activity in both knees during exercise, with increased vastus lateralis activity compared to vastus medialis activity. The purpose of the study was to use electromyographic (EMG) biofeedback training to train the patient to equalize vastus medialis and vastus lateralis EMG activity during exercise. After 11 and 13 training sessions for the left and right knees, respectively, differences between vastus medialis and vastus lateralis activity had markedly decreased. Following the termination of biofeedback training, EMG activity during exercise showed a return toward baseline levels. Several concomitant changes in psychological and physical function were noted. These results suggested that EMG biofeedback can be used to train vastus medialis and vastus lateralis activity in total knee replacement patients, and that biofeedback training may produce positive benefits in other functional areas.     

Ultrastructure of skeletal muscle fibers in monkeys after space flight

It is known that exposure of humans and animals to microgravity causes reduction in the cross-sected area of muscle fibers and muscle atrophy. These changes also involve ultrastructural alterations in muscle fibers. Therefore primates, that are physiologically close to humans, are to be examined to help a better understanding of the nature of these ultrastructural changes is muscles and muscle fibers. Although failed to find any relevant published data on the quantitative aspects of ultrastructural changes in muscle fibers of space-flown primates we believe that it is important to examine these aspects. The postflight study of monkey's m. soleus, and m. vastus lateralis did not reveal any significant changes in volume density of the myofibrillar apparatus. Mitochondria of m. soleus showed a distinct reduction in volume density, being more obvious in the subsarcolemmal zone than in the central one. Mitochondria of m. vastus lateralis showed a decrease (P > 0.05) in volume density. Following the flight, m. soleus and m. vastus lateralis of the monkeys showed a significant increase in the mean area of myofibrils, and a trend towards a decrease in the number of myofibrils per 100 micron 2. Besides, m. soleus showed a significant increase in the mean area of mitochondria, and a trend towards a decrease in the number of mitochondria per 100 micron 2. In m. vastus lateralis of the monkeys after space flight the number opf mitochondria tended to decrease and the mean area showed differential changes. It can be postulated that these phenomena may be associated with a reduction in the diffusion surface of mitochondria resulting from the diminished myofibrillar volume.     

Effect of pedaling rates and myosin heavy chain composition in the vastus lateralis muscle on the power generating capability during incremental cycling in humans

In this study, we have determined power output reached at maximal oxygen uptake during incremental cycling exercise (P(I, max)) performed at low and at high pedaling rates in nineteen untrained men with various myosin heavy chain composition (MyHC) in the vastus lateralis muscle. On separate days, subjects performed two incremental exercise tests until exhaustion at 60 rev min(-1) and at 120 rev min(-1). In the studied group of subjects P(I, max) reached during cycling at 60 rev min(-1) was significantly higher (p=0.0001) than that at 120 rev min(-1) (287+/-29 vs. 215+/-42 W, respectively for 60 and 120 rev min(-1)). For further comparisons, two groups of subjects (n=6, each) were selected according to MyHC composition in the vastus lateralis muscle: group H with higher MyHC II content (56.8+/-2.79 %) and group L with lower MyHC II content in this muscle (28.6+/-5.8 %). P(I, max) reached during cycling performed at 60 rev min(-1) in group H was significantly lower than in group L (p=0.03). However, during cycling at 120 rev min(-1), there was no significant difference in P(I, max) reached by both groups of subjects (p=0.38). Moreover, oxygen uptake (VO(2)), blood hydrogen ion [H(+)], plasma lactate [La(-)] and ammonia [NH(3)] concentrations determined at the four highest power outputs completed during the incremental cycling performed at 60 as well as 120 rev min(-1), in the group H were significantly higher than in group L. We have concluded that during an incremental exercise performed at low pedaling rates the subjects with lower content of MyHC II in the vastus lateralis muscle possess greater power generating capabilities than the subjects with higher content of MyHC II. Surprisingly, at high pedaling rate, power generating capabilities in the subjects with higher MyHC II content in the vastus lateralis muscle did not differ from those found in the subjects with lower content of MyHC II in this muscle, despite higher blood [H(+)], [La(-)] and [NH(3)] concentrations. This indicates that at high pedaling rates the subjects with higher percentage of MyHC II in the vastus lateralis muscle perform relatively better than the subjects with lower percentage of MyHC II in this muscle.     

Relationship between EMG signals and force in human vastus lateralis muscle using multiple bipolar wire electrodes.

This paper describes the relationship between knee extension force and EMG signals detected by multiple bipolar wire electrodes inserted into the human vastus lateralis muscle under isometric conditions. Six healthy male volunteers participated in this study. Eight pairs of bipolar wire electrodes were inserted into the right vastus lateralis muscle and the EMG data were simultaneously detected and analyzed. The EMG raw data and individual force-IEMG relations were influenced by the location of the electrode inserted into the muscle. The force and IEMG relationship averaged across subjects detected from the eight electrodes, however, showed almost the same linear correlation in spite of different electrode locations. No linear correlation was observed between MdF and the knee extension force. This result suggests that, if all of the muscle fibers participate in the same action at the same time, the averaged normalized IEMG from any places using wire electrodes could reflect the total activities of that muscle even if the muscle is large.     

Correlation between timed up and go test and skeletal muscle tensiomyography in female nursing home residents

Objectives:Tensiomyography (TMG) derived contraction time (Tc) and amplitude (Dm) are related to muscle fibre composition and to muscle atrophy/tone, respectively. However, the link between mobility and TMG-derived skeletal muscle contractile properties in older persons is unknown. The aim of the study was to correlate lower limb skeletal muscle contractile properties with balance and mobility measures in senior female residents of retirement homes in Austria.Methods:Twenty-eight female participants (aged from 67-99 years) were included in measurements of contractile properties (TMG) of four skeletal muscles: vastus lateralis, vastus medialis, biceps femoris and gastrocnemius medialis. Their balance and mobility performance was measured using a timed up and go test (TUG).Results:Time needed to complete TUG is negatively correlated to biceps femoris (r= -0.490; p= 0.008), vastus lateralis (r= -0.414; p=0.028) and vastus medialis (r= -0.353; p=0.066) Dm and positively correlated to vastus lateralis Tc (r=0.456; p=0.015). Overall, vastus lateralis Tc and vastus medialis Dm explained 37% of TUG time variance.Conclusions:Our study demonstrates that TMG-derived quadriceps muscle contractile parameters are correlated with the balance and mobility function in female nursing home residents.     

Biofeedback as a means to alter electromyographic activity in a total knee replacement patient

This paper presents a single case controlled study of a 75-year-old male having bilateral total knee replacement. Baseline EMG recordings demonstrated differential levels of vastus medialis and vastus lateralis muscle activity in both knees during exercise, with increased vastus lateralis activity compared to vastus medialis activity. The purpose of the study was to use electromyographic (EMG) biofeedback training to train the patient to equalize vastus medialis and vastus lateralis EMG activity during exercise. After 11 and 13 training sessions for the left and right knees, respectively, differences between vastus medialis and vastus lateralis activity had markedly decreased. Following the termination of biofeedback training, EMG activity during exercise showed a return toward baseline levels. Several concomitant changes in psychological and physical function were noted. These results suggested that EMG biofeedback can be used to train vastus medialis and vastus lateralis activity in total knee replacement patients, and that biofeedback training may produce positive benefits in other functional areas.The authors wish to express thanks to Dr. Karen Gil for her helpful comments on a draft of this article, and Christianne Herman and Allison Roodman for their help in data collection and entry.     

Regulation of PDH in human arm and leg muscles at rest and during intense exercise

To test the hypothesis that pyruvate dehydrogenase (PDH) is differentially regulated in specific human muscles, regulation of PDH was examined in triceps, deltoid, and vastus lateralis at rest and during intense exercise. To elicit considerable glycogen use, subjects performed 30 min of exhaustive arm cycling on two occasions and leg cycling exercise on a third day. Muscle biopsies were obtained from deltoid or triceps on the arm exercise days and from vastus lateralis on the leg cycling day. Resting PDH protein content and phosphorylation on PDH-E1 alpha sites 1 and 2 were higher (P < or = 0.05) in vastus lateralis than in triceps and deltoid as was the activity of oxidative enzymes. Net muscle glycogen utilization was similar in vastus lateralis and triceps ( approximately 50%) but less in deltoid (likely reflecting less recruitment of deltoid), while muscle lactate accumulation was approximately 55% higher (P < or = 0.05) in triceps than vastus lateralis. Exercise induced (P < or = 0.05) dephosphorylation of both PDH-E1 alpha site 1 and site 2 in all three muscles, but it was more pronounced at PDH-E1 alpha site 1 in triceps than in vastus lateralis (P < or = 0.05). The increase in activity of the active form of PDH (PDHa) after 10 min of exercise was more marked in vastus lateralis ( approximately 246%) than in triceps ( approximately 160%), but when it was related to total PDH-E1 alpha protein content, no difference was evident. In conclusion, PDH protein content seems to be related to metabolic enzyme profile, rather than myosin heavy chain composition, and less PDH capacity in triceps is a likely contributing factor to higher lactate accumulation in triceps than in vastus lateralis.     

Association between walking ability and trunk and lower-limb muscle atrophy in institutionalized elderly women: a longitudinal pilot study

Background

The aim of this study was to investigate the association between walking ability and muscle atrophy in the trunk and lower limbs.

Methods

Subjects in this longitudinal study were 21 elderly women who resided in nursing homes. The thicknesses of the following trunk and lower-limb muscles were measured using B-mode ultrasound: rectus abdominis, external oblique, internal oblique, transversus abdominis, erector spinae, lumbar multifidus, psoas major, gluteus maximus, gluteus medius, gluteus minimus, rectus femoris, vastus lateralis, vastus intermedius, biceps femoris, gastrocnemius, soleus, and tibialis anterior. Maximum walking speed was used to represent walking ability. Maximum walking speed and muscle thickness were assessed before and after a 12-month period.

Results

Of the 17 measured muscles of the trunk and lower limbs, age-related muscle atrophy in elderly women was greatest in the erector spinae, rectus femoris, vastus lateralis, vastus intermedius, and tibialis anterior muscles. Correlation coefficient analyses showed that only the rate of thinning of the vastus lateralis was significantly associated with the rate of decline in maximum walking speed (r = 0.518, p < 0.05).

Conclusions

This longitudinal study suggests that reduced walking ability may be associated with muscle atrophy in the trunk and lower limbs, especially in the vastus lateralis muscle, among frail elderly women.     

The influence of 5 weeks of ULLS and resistance exercise on vastus lateralis and soleus myosin heavy chain distribution

We examined the distribution of the myosin heavy chain (MHC) isoforms (I, IIa, IIx) of the leg muscles of three groups of men and women (40 +/- 8y) that completed unilateral lower limb suspension only (ULLS), ULLS plus resistance exercise (ULLS+RE), or RE only (RE) for 5 weeks. Muscle biopsies were obtained pre and post from the vastus lateralis of all three groups and the soleus of the ULLS group. Distributions of all three MHC isoforms in the vastus lateralis were unchanged (p<0.05) from pre to post with ULLS. The soleus muscle, which contained no measurable IIx isoform, was also unchanged (p< 0.05) from pre to post ULLS. These results suggest that the percent distribution of the MHC isoforms per unit muscle protein in both the vastus lateralis and soleus does not change during the first five weeks of simulated microgravity. Further, resistance exercise during five weeks of ULLS or ambulation does not appear to alter the MHC distribution per unit muscle protein of the vastus lateralis.     

Length and moment arm of human leg muscles as a function of knee and hip-joint angles

Lengths of muscle tendon complexes of the quadriceps femoris muscle and some of its heads, biceps femoris and gastrocnemius muscles, were measured for six limbs of human cadavers as a function of knee and hip-joint angles. Length-angle curves were fitted using second degree polynomials. Using these polynomials the relationships between knee and hip-joint angles and moment arms were calculated. The effect of changing the hip angle on the biceps femoris muscle length is much larger than that of changing the knee angle. For the rectus femoris muscle the reverse was found. The moment arm of the biceps femoris muscle was found to remain constant throughout the whole range of knee flexion as was the case for the medial part of the vastus medialis muscle. Changes in the length of the lateral part of the vastus medialis muscle as well as the medial part of the vastus lateralis muscle are very similar to those of vastus intermedius muscle to which they are adjacent, while those changes in the length of the medial part of the vastus medialis muscle and the lateral part of the vastus lateralis muscle, which are similar to each other, differ substantially from those of the vastus intermedius muscle. Application of the results to jumping showed that bi-articular rectus femoris and biceps femoris muscles, which are antagonists, both contract eccentrically early in the push off phase and concentrically in last part of this phase.     

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.