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PubMed1989

Variability in muscle fibre areas in whole human quadriceps muscle: how to reduce sampling errors in biopsy techniques.

A single biopsy is a poor estimator of the muscle fibre cross-sectional area (CSA) for a whole human muscle because of the large variability in the fibre area within a muscle. To determine how the sampling errors in biopsy techniques can be reduced, data on the CSA of type 1 and type 2 fibres obtained from cross-sections of whole vastus lateralis muscle of young men, have been analysed statistically. To obtain a good estimate of the mean fibre CSA in a biopsy, measuring all fibres in that biopsy gives the best result. To obtain a good estimate of the mean fibre CSA for a whole muscle, the number of biopsies has a much greater influence on the sampling error than the number of fibres measured in each biopsy, but the number of biopsies needed to obtain a given sampling error can vary by a factor of two. If the fibre CSA in three or more biopsies is measured, it is sufficient to measure only 25 fibres in each biopsy. If less than three biopsies are taken, there is no worthwhile reduction in sampling error when more than 100 fibres are measured. To determine the mean fibre CSA for a whole group of individuals, our preference is to maximize the number of individuals, and only take single biopsies. In conclusion, to determine the mean fibre CSA for this particular muscle with a certain precision, we suggest analysis of three biopsies, taken from different depths of the muscle, and measurement of 25 fibres in each biopsy.

Adolescent↗

PubMed1989

Variability in muscle fibre areas in whole human quadriceps muscle. How much and why?

To determine the variability in fibre areas in the human vastus lateralis muscle, cross-sections (15 microns) of whole autopsied muscles from eight young men have been prepared, and the cross-sectional area (CSA) of 375 type 1 and 375 type 2 fibres has been measured in five different regions throughout each muscle. The CSA of both fibre types varied significantly within all muscle cross-sections. Fibres in the deep parts of the muscle were larger than superficially. There was a significant correlation between the CSA of the two fibre types within each region: if a fibre of a given type was small, or large, the other fibre type was also small, or large. The CSA of type 2 fibres was larger than the CSA of type 1 fibres in 26 of the 40 regions: regions with type 1 fibres larger than type 2 fibres were mostly (71%) found deep in the muscle. The standard deviation of the CSA of type 1 fibres was significantly larger than for type 2 fibres in 35 of the 40 regions. In conclusion, the CSA of the different fibre types in the vastus lateralis of young men varies non-randomly. The pattern of variation, both throughout the muscle and in small sample regions, supports the general opinion that the functional demands placed on the fibre population are an important factor in the development of the fibre properties.

Adenosine Triphosphatases↗

PubMed1991

Variability in muscle fibre areas in whole human quadriceps muscle: effects of increasing age.

Cross-sections of whole vastus lateralis muscle from 20 men, 19 to 84 years of age, were prepared, and the cross-sectional area (microns2) of 375 type 1 and 375 Type 2 fibres was measured in five different regions throughout each muscle. In muscles from the old individuals, the mean CSA of Type 2 fibres was on average nearly 35% smaller (P less than 0.001) while the mean CSA of Type 1 fibres was on average just over 6% smaller (NS) than in muscles from the young individuals. There was a highly significant (P less than 0.001) variation in the mean CSA of both fibre types within all muscles. In the old muscles, there was no significant difference in mean fibre CSA between deep and superficial parts while in the young muscles the mean fibre CSA was significantly (P less than 0.05) larger in deep regions than superficially. The range of the fibre CSA was larger in the old muscles with an increased number of both hypotrophied and atrophied fibres as well as large, sometimes very large, fibres. The standard deviation of the fibre CSA of Type 2 fibres was significantly (P less than 0.001) larger than for Type 1 fibres in 60% of the regions of the old muscles compared to 12.5% of the regions of the young muscles, but the standard deviation for the whole muscles was more or less unaffected with increasing age. In the old age group, there were fewer muscles and regions with a correlation between the CSA of Type 1 and Type 2 fibres than in the young age group. In conclusion the age-related changes in the mean fibre CSA, and in the pattern of variation in fibre CSA throughout the muscle and in small sample regions, suggest a combination of a progressive denervation process and an altered physical activity level as the two major mechanisms underlying the effects of normal development and ageing on the human vastus lateralis muscle.

Adult↗

PubMed1986

The time course and magnitude of blood flow changes in the human quadriceps muscles following isometric contraction.

Blood velocities in the human femoral artery were measured using pulsed bidirectional Doppler-ultrasound equipment before, during and after single isometric contractions of the quadriceps muscle group. After contraction periods lasting more than 20 s (long) and of tensions from 10% up to 75% of maximal voluntary contraction (m.v.c.), an increase in blood velocities of seven to eight times the resting level was observed. Estimated maximal volume flow to the whole leg during the post-contraction hyperaemic phase calculated from these blood velocity measurements and vessel diameter (measured with echo-ultrasound equipment) was in two of the subjects 2.4 l/min (female) and 4.4 l/min (male), respectively. In the latter, this estimate fitted very well with results obtained using a venous thermo-dilution method. When using computer tomography to estimate the volume of the quadriceps muscle group, the calculated maximum flow to this muscle group in the post-contraction hyperaemic phase was approximately 175 (female) and 185 (male) ml/min. 100 ml muscle, respectively. This was about forty times the estimated resting volume flow to this muscle of 4.7 (female) and 4.5 (male) ml/min. 100 ml muscle. The length of the post-contraction hyperaemia after short (less than 10 s) contraction periods was 12-13 s, by which time velocities had reached 25% above the precontraction level. After long contractions, the corresponding values were 23-25 s. By contrast, previous plethysmographic observations by others indicate that postcontraction hyperaemias following long contractions last 10-15 min. There was a marked difference between the times taken to reach maximal velocity in the hyperaemic phase when comparing short and long contractions. Maximal velocity was reached four to six cardiac cycles following short periods of contraction but during the very first heart beat after long periods of contractions. The present observations are compatible with the hypothesis that locally released metabolites or hormones play a dominant role in the regulation of the post-contraction hyperaemia. Since during the short contraction periods maximal velocity was reached only after some seconds, whereas with the longer contraction periods it was reached during the first heart beat, it is suggested that these metabolites are released at some distance from the resistance vessels and that some time is needed for diffusion.

Adult↗

PubMed2003

Primary hydatid disease of the quadriceps muscle: a rare localization.

BACKGROUND: Hydatidosis is a protozoal infestation which generally involves the liver and the lungs. Primary skeletal muscle hydatidosis without involving the thoracic and abdominal organs is extremely rare. METHODS: A 48-year-old farmer presented with a mass in the quadriceps muscle that had persisted for 10 years. Clinical and radiological investigations revealed a primary hydatid cyst of the vastus medialis of the quadriceps muscle. We did not find any visceral organ involvement. Wide excision was performed without destroying the cyst wall. Then 400 mg albendazole was given daily for 3 months postoperatively. RESULTS: At the 7th postoperative month, the patient was symptom-free, and the laboratory test results were in the normal ranges. CONCLUSION: Primary muscular hydatidosis is a rare disease and should be kept in mind in the diagnostic work-up of a cystic mass of a skeletal muscle.

Albendazole↗

PubMed2000

Contractile properties and fatigue of quadriceps muscles in multiple sclerosis.

Functional characteristics of electrically stimulated quadriceps muscles of patients with multiple sclerosis (MS) were determined to investigate whether adaptations in muscle properties contribute to the higher fatigability of these patients. The estimated maximal isometric force generating capacity of MS patients was only 11.2% (P < 0.05) lower than control subjects. However, the patients were only able to voluntarily exert 75 +/- 22% (n = 12) of their maximal capacity, against 94 +/- 6% (n = 7) for the control subjects. There were no differences in muscle speed, suggesting that muscle fiber distribution was not different in the MS patients due to reduced muscle usage. During a series of repeated contractions, greater decrements occurred in isometric force and in maximal rate of force rise in the MS patients (by 31.3 +/- 10.3% and 50.1 +/- 10.0%, respectively; n = 13) than control subjects (23.8 +/- 6.6% and 39.0 +/- 8.1%, n = 15), suggesting a lower oxidative capacity. The results indicate that increasing the mass of their muscles by training may help to reduce the excessive muscle fatigue of MS patients.

Adult↗

PubMed1991

Acoustic myographic activity increases linearly up to maximal voluntary isometric force in the human quadriceps muscle.

Sounds produced during voluntary isometric contractions of the quadriceps muscle were recorded by acoustic myography (AMG) in seven healthy adults. With the subject seated, surface AMG and electromyography (EMG) were recorded over rectus femoris (RF) during isometric contractions, at different levels of maximum voluntary force. The AMG and EMG signals were amplified and integrated (IAMG and IEMG). The relationships between force and IAMG (r = 0.98 +/- 0.01, mean +/- 1 SD) and force and IEMG (r = 0.99 +/- 0) were linear in all subjects. The results for EMG confirm previous reports but those for AMG differ from the relationships reported for other muscles. Physiological and technical explanations are proposed for these differences and the necessity for further validation of the AMG technique is stressed.

Acoustics↗

PubMed1975

The effect of circulatory occlusion on isometric exercise capacity and energy metabolism of the quadriceps muscle in man.

Occlusion of the circulation to the quadriceps muscle for 20 min resulted in decreases in the muscle ATP and phosphorylcreatine (PC) contents of 1 and 32 per cent, respectively, and increases in ADP and AMP of 7 and 37 per cent. Decrease in PC was statistically significant after 4 min of occlusion, suggesting that the local intramuscular oxygen store was sufficiently depleted at this time as to be limiting to normal mitochondrial function. Pyruvate and lactate concentrations in muscle and the lactate to pyruvate ratio were significantly increased after 15 min of occlusion but not before. The calculated local oxygen store in the muscle was 2.0 mmol O2 - (kg dry muscle)-1. Local oxygen store depletion after 4 and 10 min of occlusion was estimated to be 40-50 and 90-100 per cent complete. Increasing time of pre-exercise occlusion resulted in decreased isometric endurance capacity. The observed decreases in endurance, however, were far greater than could be accounted for by any parallel decrease in the local muscle energy stores.

Adenosine Diphosphate↗

PubMed1993

Shortening of patellar ligament and patella baja with improvement of quadriceps muscle strength after high tibial osteotomy.

One hundred and eight osteoarthritic knees that had high tibial osteotomy were examined, in the length of the patellar ligament, patellar height, and the strength of the quadriceps muscle. Patellar ligament shortening occurred until one year after surgery. Subsequently, shortening was not observed to be significant over a 10 year followup period. Using Insall-Salvati ratio, a majority of knees seemed to have lower patellae, because of the shortening of the patellar ligament. However, using patellotibial distance, 68 percent of patellae maintained the same height as preoperatively and 26 percent became patella baja. The strength of the quadriceps muscle increased postoperatively, reached the maximum at 2 years, and preserved the same strength over 10 years. Patellar ligament shortening and patella baja were probably thought to be caused by the biological adaptation of the extensor mechanism and the shrinking of the scar tissue in and around the postoperative patellar ligament.

Adaptation, Physiological↗

PubMed2000

[Bilateral dysfunction of the quadriceps muscle after unilateral cruciate ligament rupture with concomitant injury central activation deficit].

The aim of the study was to investigate the ability to activate the quadriceps femoris muscle voluntarily in patients after severe knee injuries and it's influence on muscle function. 33 male patients after ACL-rupture with concomitant injuries were investigated with a twitch-interpolation-method to determine the maximal voluntary contraction force (MVC) and the ability to activate the quadriceps muscle voluntarily. The results were compared to a previously investigated group of patients after isolated ACL-rupture and to an aged-matched control group. The patients with extensive knee injuries presented a significant higher deficit of voluntary quadriceps muscle activation on the injured (78.8 +/- 2.09%, mean +/- SEM) and equally on the uninjured side (78.9 +/- 1.91%) compared to the patients after isolated ACL-rupture and to controls. A minor MVC-deficit of the patients quadriceps muscle of the uninjured side could be explained by the voluntary activation deficit alone, the major MVC deficit of the injured side by muscle atrophy and a voluntary activation deficit. The activation deficit is probably the underlying reason for persisting muscle wasting and [not readable: see text]

Adolescent↗

PubMed2004

The contribution of the medial retinaculum and quadriceps muscles to patellar lateral stability--an in-vitro study.

Patellofemoral joint stability is a result of the restraining effects of the quadriceps muscles, the retinacular structures, and engagement of the bones. The role and significance of these mechanisms in restraining patellar lateral displacement was investigated in this study by measuring the force needed to cause 5 mm lateral displacement (i.e. the mechanical stability, or 'stabilising force') of the patella. Six cadaver knees had 175 N quadriceps load distributed among three muscle groups. With a force ratio matching the muscles physiological cross sectional areas, no significant change occurred in the patellar stabilising force between 0 and 60 degrees knee flexion, but a significant increase occurred between 60 and 90 degrees, presumably reflecting the contribution of the femoral groove. Variation of the quadriceps force distribution changed the stability significantly. Relaxing the vastus lateralis increased the patellar lateral stabilising force 52+/-8%, while relaxing vastus medialis reduced the stabilising force 47+/-9%. The minimum stabilising force was at 30 degrees knee flexion. Transection of the medial retinaculum reduced the lateral stabilising force 34% in the extended knee. This effect disappeared by 45 degrees knee flexion. It was concluded that the quadriceps muscles had a significant and consistent effect across the whole range of knee flexion, but the contribution of the medial retinaculum was restricted to extended knee postures.

Aged↗

PubMed1997

Contractile properties and fiber type distribution of quadriceps muscles in adults with childhood-onset growth hormone deficiency.

Adults with GH deficiency (GHD) report weakness and fatigability. The origin of such symptoms is still debated. This work aimed to clarify whether weakness and fatigability depend on impairment of skeletal muscle contractile capacity. Five males with childhood-onset GHD (age +/- SE, 29.6 +/- 1.9) and 13 age- and sex-matched controls were enrolled in the study. Quadriceps muscle cross-sectional area (CSA), strength, twitch characteristics, and fatigue index of voluntary and electrically evoked contractions were determined in vivo in all subjects. Fiber type distribution and CSA of identified types of skeletal fibers were determined on needle biopsy samples of the vastus lateralis muscle of all subjects. Fiber type distribution was assessed on the basis of myosin heavy chain (MHC) isoform composition determined by electrophoresis on polyacrylamide gels. Fiber CSA was determined on cross-cryosections of fiber bundles immunostained by monoclonal antibodies against MHC isoforms. Absolute values of strength and fiber CSA of quadriceps were significantly lower in patients affected by GHD than in controls. However, once strength and fiber CSA were normalized for quadriceps CSA and subject height, respectively, differences disappeared. No difference was found between GHD patients and controls for quadriceps muscle twitch characteristics, fatigue index, and fiber type distribution. The results reported here suggest that weakness and fatigability in childhood-onset GHD do not have a skeletal muscle origin.

Adult↗

PubMed2005

Correlation of back pain, compression fracture and quadriceps muscle strength with bone mineral density in renal insufficiency patients.

AIM: The purpose of this study was to evaluate bone mineral density (BMD), bone parameters, complete blood count, erythrocyte sedimentation rate, electrolyte values, back pain, compression fracture and quadriceps muscle strength in mild and moderate renal insufficiency patients. METHODS: Thirty-six female, 3 male, patients with the diagnosis of osteoporosis in addition to mild or moderate chronic renal insufficiency who were followed in Istanbul University, Cerrahpasa Faculty of Medicine, Physical Therapy and Rehabilitation Department, Osteoporosis and Nephrology Outpatient Clinics between March 2003 and March 2004, were included in the study. In the control group there were 17 female, 5 male patients with osteoporosis but without renal insufficiency. The inclusion criteria were to have osteoporosis, be aged between 40-70 with a creatinine clearance between 30-70 mL/min in the case group, >70 mL/min in the control group. The patients whose creatinine clearance was <30 mL/min, and whose BMD was normal or osteopenic even though creatinine clearance was >30 mL/min were excluded from the study. RESULTS: There was no significant difference with respect to back pain, compression fracture and quadriceps muscle strength between the 2 groups. The mean value of neck BMD, T and Z score were significantly lower in the case group (P<0.05). CONCLUSIONS: As a conclusion, PTH related bone disease had an important effect on BMD, although, the risk factors for osteoporosis were equally important. In various researches, the relationship between BMD values and history of fracture in renal osteodystrophy patients could not be shown. In our study, the history of prior fracture or fracture in the family were important risk factors for osteoporosis. Renal osteodystrophy patients had low BMD values in mild and moderate stages of the disease. Prior fracture as well as osteoporotic fractures in the family should be part of a comprehensive evaluation of the patient.

Adult↗

PubMed2005

Altered hamstring-quadriceps muscle balance in patients with knee osteoarthritis.

BACKGROUND: To compare hamstring to quadriceps muscle coactivity during level walking, stair ascent, and stair decent between individuals with and without knee osteoarthritis. METHODS: In a cross-sectional study, subjects with grade II knee osteoarthritis (n = 26), healthy age- and gender-matched (n = 20) and healthy, young adults (n = 20) performed three activities of daily living. During the stance phase of these activities surface electromyography was measured. Two coactivity ratios were computed, the biceps femoris to vastus lateralis ratio and the ratio of the biceps femoris EMG activity relative to the EMG activity measured during contraction- and velocity-specific maximal voluntary biceps femoris contraction, i.e., biceps femoris to maximal biceps femoris activity. FINDINGS: Subjects with knee osteoarthritis had significantly higher coactivity than age-matched healthy adults and young adults and healthy adults had more coactivity than young adults regardless the type of coactivity ratio. The biceps femoris to vastus lateralis ratio yielded 25% higher coactivity value than the biceps femoris to maximal biceps femoris ratio (P < 0.0001). The EMG activity of the vastus lateralis relative to maximal vastus lateralis EMG activity was 92% in subjects with knee osteoarthritis, 57% in age-matched controls, and 47% in young adults (P < 0.0001). INTERPRETATION: Patients with knee osteoarthritis revealed increased hamstring muscle activation while executing activities of daily living. Altered muscle activation at the knee may interfere with normal load distribution in the knee and facilitate disease progression. Therapeutic interventions should focus not only on quadriceps strengthening but also on improving muscle balance at the knee.

Activities of Daily Living↗

PubMed1983

Size and composition of the calf and quadriceps muscles in Duchenne muscular dystrophy. A tomographic and histochemical study.

Calf and quadriceps muscle size and composition have been examined in 5 control subjects and 12 boys (aged 7-18 years) with Duchenne muscular dystrophy using computed tomography (CT) and quantitative histochemistry of needle biopsy samples of muscle. In assessing the size of leg muscles it was found that in control subjects the muscle cross-sectional area was related to the cross-sectional area of the femur. The calf muscles in the patients were enlarged both relative to the quadriceps and absolutely when related to the cross-sectional area of the femur used as an index of stature. The enlargement of the calf was the result of accumulations of fat and connective tissue in the presence of relatively normal (compared to femur size) amounts of muscle tissue. Although hypertrophied muscle fibres were a feature of the biopsy samples in the calf the extent of this was insufficient to contribute appreciably to the total muscle enlargement.

Adolescent↗

PubMed1993

Limb blood flow, cardiac output and quadriceps muscle bulk following spinal cord injury and the effect of training for the Odstock functional electrical stimulation standing system.

As part of the assessment of the Odstock functional electrical stimulation (FES) standing system for mid to low thoracic lesion spinal cord injured (SCI) subjects, cardiac output, high blood flow and quadriceps muscle thickness were measured before and following an electrical stimulation muscle retraining programme. The same parameters were also measured in a group of uninjured subjects and in SCI subjects. It was found that there was no difference in cardiac output between the groups. However thigh blood flow was found to be around 65% of normal values in the spinally injured group. This returned to normal values following the retraining programme. The quadriceps muscle wasted to approximately 50% of its original thickness in the first 3 weeks following spinal cord injury. The retraining programme increased the muscle thickness to near normal values.

Adult↗

PubMed1992

Effects of functional electrical stimulation (FES) on evoked muscular output in paraplegic quadriceps muscle.

In order to assess the effects of FES on muscle output, chronic electrical stimulation of the quadriceps muscle was applied for half an hour twice a day for 2 months, in 10 thoracic level traumatic paraplegic patients. Results concerning torque (at 6 different muscle lengths) and fatigue were measured using a strain gauge transducer in isometric condition, and compared with the findings in 15 paraplegic patients who had not received electrical stimulation, and with 10 able bodied subjects with normal motor functions. With training, muscle strength was very significantly improved whilst fatigue resistance remained at a low level. The peak torque was not found to be of the same muscle length when comparing paraplegics and control subjects; it seemed to demonstrate that length-tension relationship of the muscular actuator was changing when it was electrically activated. Moreover, the force recorded in paraplegics remained markedly lower than in able bodied people.

Electric Stimulation↗

PubMed1985

The effect of long-term circulatory occlusion on pH and energy metabolism of the quadriceps muscle in man.

The effect of up to 2.5 h circulatory occlusion on muscle pH and energy metabolism of the quadriceps muscle was studied in 13 patients operated on for an inveterate knee injury. Muscle samples were taken by the percutaneous needle biopsy technique at different times during the arterial occlusion and after restoration of circulation. Energy was provided by a complete utilization of phosphocreatine and by a low rate of glycolysis during 2 h of occlusion. The ATP level remained unchanged throughout the occlusion period. Muscle pH decreased from 7.0-7.1 to about 6.8 after 2 h occlusion. Muscle pH was essentially normalized within 20 min after restoration of the blood flow.

Adenosine Triphosphate↗