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At least 631 records · Page 35Linked to original sources

PubMed2000

Quadriceps and hamstrings peak torque ratio changes in persons with chronic anterior cruciate ligament deficiency.

STUDY DESIGN: Cross-sectional analytical study in which subjects served as their own controls. OBJECTIVE: To assess the concentric and eccentric peak torque in the hamstrings and quadriceps muscles, hamstrings/quadriceps amplitude ratios, and lean thigh volume differences in the involved and uninvolved limb of subjects with anterior cruciate ligament (ACL) deficiency. BACKGROUND: [corrected] Although the hamstrings/quadriceps ratios for concentric and eccentric activity have been studied, the more functional eccentric hamstings/concentric quadriceps ratio has not been previously described in chronic ACL deficient individuals. METHODS AND MEASURES: Eighteen subjects (36 +/- 11 years; 12 men, 6 women) with unilateral chronic ACL deficiency were recruited. Changes in activities of daily living, lean thigh volume (LTV) and isokinetic peak torque and total work capacity of both the quadriceps and hamstring muscles were investigated. The uninvolved limb served as control. RESULTS: Eccentric quadriceps peak torque in the ACL deficient limb was reduced by 38% compared with the 16% reduction of concentric quadriceps peak torque. Eccentric hamstrings peak torque was reduced by 15% compared with an 8% reduction in concentric hamstrings peak torque. LTV in the ACL deficient limb was 11% smaller than the uninvolved limb (3,541 +/- 899 vs 3,161 +/- 742 cc, uninvolved versus ACL deficient limb). The relation between LTV and eccentric peak torque was stronger in the uninvolved (r = 0.82) compared with the ACL deficient limb (r = 0.66). The eccentric hamstrings/quadriceps ratio was significantly higher in the ACL deficient (0.80 +/- 0.26) compared with the uninvolved limb (0.55 +/- 0.13). However, the eccentric hamstrings/concentric quadriceps ratio was similar between ACL deficient (0.75 +/- 0.17) and uninvolved (0.77 +/- 0.20) limbs, while the concentric hamstrings/eccentric quadriceps ratio was significantly higher in the ACL deficient (0.79 +/- 0.26) compared with the uninvolved (0.50 +/- 0.14) limb. CONCLUSIONS: Quadriceps and hamstrings peak torque values were significantly decreased in ACL deficient compared with the uninvolved limb. Eccentric muscle activity was affected to a greater degree than concentric muscle activity in the quadriceps muscle after ACL injury. The eccentric hamstrings/concentric quadriceps ratios were similar in ACL deficient and normal limbs, indicating that muscular co-ordination strategies may have been altered to maintain normal limb activity despite the strength losses particularly evident in quadriceps muscle function.

Adult↗

PubMed2001

Weight gain does not preclude increased ubiquitin conjugation in skeletal muscle: an exploratory study in tumor-bearing mice.

BACKGROUND AND HYPOTHESIS: At least 13 studies have shown that the ubiquitin-proteasome system mediates muscle wasting in weight-losing cancer subjects. We hypothesized that cancer itself may activate the ubiquitin-proteasome system, regardless of weight loss. METHODS: We utilized hybrid mice obtained by crossing Mouse Mammary Tumor Virus-Transforming Growth Factor-alpha (TGF-alpha) mice with the Lep(ob) strain. Five hybrid MMTV-TGF-alpha heterozygous Lep(+)Lep(ob) female mice with mammary tumors were used; 4 nontransgenic heterozygous Lep(+)Lep(ob) female mice served as controls. Ubiquitin conjugates were quantitated from hamstring and paraspinal muscles by Western blotting. Myocyte apoptosis was determined by a modified TUNEL assay. RESULTS: All mice gained weight, even after tumor development. Higher concentrations of muscle ubiquitin conjugates were seen in the 5 tumor-bearing, TGF-alpha transgenic mice as compared with the 4 non-tumor-bearing mice: median (range) in arbitrary densitometric units: 0.67 (0.22-4.59) versus 0.18 (0.08-0.44) in hamstring muscle and 0.56 (0.23-20.15) versus 0.18 (0.08-0.25) in paraspinal muscle (p = 0.04 and p = 0.04, respectively; Mann-Whitney U test). Apoptosis was not seen in any muscle sample studied. CONCLUSIONS: Ubiquitin conjugates are increased in the skeletal muscle of tumor-bearing mice in the absence of weight loss. Such activation is not seen in the skeletal muscle on non-tumor-bearing mice. Further studies might focus of whether this observation is relevant to cancer-associated wasting of lean tissue.

Adenocarcinoma↗

PubMed2003

Muscle activation patterns of selected lower extremity muscles during stepping and cutting tasks.

Lower extremity muscle activations during crossover and side step cut tasks are hypothesized to play an important role in controlling knee motion, and therefore, impact the design of knee injury prevention and rehabilitation programs. However, the contribution of lower extremity muscles to frontal and transverse plane moments during cutting tasks is unclear. The purpose of this study was to compare the muscle activation patterns of selected lower extremity muscles (vastus lateralis, medial/lateral hamstrings and medial/lateral gastrocnemius) of subjects performing a stepping down and side step cut, a stepping down and crossover cut and an equivalent straight ahead task. Ground reaction force was used to determine the cut angle, stance time and compare the lower limb loading during each task. Electromyography data during all tasks were normalized to the average activation during the straight ahead tasks to determine relative changes in muscle activation between the straight ahead and different cut styles (crossover and side step). There were no differences in the pattern of muscle activation of the vastus lateralis, or lateral hamstring muscles when comparing the cutting tasks to the equivalent straight ahead task. However, the crossover cut task resulted in significantly higher muscle activation of the medial hamstrings and lateral gastrocnemius muscles relative to both the side step cut and straight ahead tasks. These results suggest the medial/lateral hamstrings and medial/lateral gastrocnemius play a role in transverse and frontal plane control during cut tasks.

Adult↗

PubMed2001

Extensibility and stiffness of the hamstrings in patients with nonspecific low back pain.

OBJECTIVE: To investigate the extensibility and stiffness of the hamstrings in patients with nonspecific low back pain (LBP). DESIGN: An experimental design. SETTING: A university laboratory for human movement analysis in a department of rehabilitation medicine. PARTICIPANTS: Forty subjects, a patient group (20) and a healthy control group (20). INTERVENTIONS: Subjects laid supine on an examination table with a lift frame, with left leg placed in a sling at the ankle. Straight leg raising, pulling force, and activity of hamstring and back muscles were recorded with electrodes. Patients indicated when they experienced tension or pain. MAIN OUTCOME MEASURES: The lift force, leg excursion, pelvic-femoral angle, first sensation of pain, and the electromyogram of the hamstrings and back muscles measured in an experimental straight-leg raising set-up. RESULTS: The patient group showed a significant restriction in range of motion (ROM) and extensibility of the hamstrings compared with the control group. No significant difference in hamstring muscle stiffness can be assessed between both groups. CONCLUSION: The restricted ROM and the decreased extensibility of the hamstrings in patients with nonspecific LBP is not caused by increased muscle stiffness of the hamstrings, but determined by the stretch tolerance of the patients.

Adult↗

PubMed2001

Viscoelastic properties and flexibility of the human muscle-tendon unit in benign joint hypermobility syndrome.

OBJECTIVE: To examine the passive energy absorption of the hamstring muscle-tendon unit in 9 women with benign joint hypermobility syndrome (BJHS) and 9 age and sex matched controls. METHODS: Resistance to stretch was measured as knee flexion moment (N.m) with an isokinetic dynamometer during passive knee extension. The angle that induced a stretch sensation without pain was the maximal stretch angle. Force, angle, angular velocity (0.09 rad/s), and electromyograph were simultaneously and continuously recorded during the stretch. Hamstring cross sectional area was obtained with magnetic resonance imaging. RESULTS: Forearm skin extensibility was greater for BJHS (3.6+/-0.5 cm) than for controls (1.3+/-0.2 cm) (p < 0.01). Similarly, the Beighton score was greater for BJHS (6.6+/-0.8) than for controls (0.4+/-0.2) (p < 0.001). Maximal stretch angle was greater for BJHS (delta1.35+/-0.07 rad) compared to controls (delta0.98+/-0.05 rad) (p < 0.001), and the corresponding peak moment was also greater for BJHS (1.3+/-0.4 Nm/cm2) than for controls (0.6+/-0.1 Nm/cm2) (p < 0.01). For a given mutual angle the passive energy absorption was the same for both groups, but at the maximal stretch angle the total area-normalized energy was greater for BJHS (0.36+/-0.04 J/cm2) than for controls (0.18+/-0.28 J/cm2) (p < 0.001). CONCLUSION: The lack of difference in passive energy absorption for a given mutual stretch angle suggests that passive properties of the muscle-tendon unit of BJHS are similar to those of controls. However, the greater maximal stretch angle and corresponding peak moment in BJHS suggests a greater subjective tolerance to passive stretch. That is, increased flexibility in BJHS is not a function of altered passive properties of the muscle-tendon complex. It remains unknown if the enhanced tolerance to passive tension plays a role in the development of musculoskeletal ailment.

Adult↗

PubMed2001

Efficacy of moist heat pack application over static stretching on hamstring flexibility.

Inadequate flexibility is a contributing factor to muscle injury, especially with respect to the hamstring muscle group. Simple therapeutic regimens capable of increasing hamstring flexibility may reduce the injury potential of athletes with below-average hamstring flexibility or history of injury. This study compared 30 seconds of static stretching with 20 minutes of heat application on hamstring flexibility. A secondary purpose was to determine the relationship between the subjects attitude toward each treatment and the efficacy of treatment. Thirty undergraduate student athletes who were current members of a Midwestern collegiate football team participated in a 2 (treatment: heat vs. stretching) by 2 (coun-terbalanced order: heat first vs. stretching first) repeated-measures design. Results indicated that significant benefits to increase hamstring flexibility could be gained by using moist heat packs in comparison with static stretching despite a perceived attitudinal bias in favor of stretching. These findings may have implications for orthopedic fitness as well as injury prevention for an athlete with prior hamstring injury or inadequate flexibility.

Adolescent↗

PubMed1999

Influence of heredity and environment on bone density in adolescent boys: a parent-offspring study.

The purpose of the present parent-offspring study was to investigate the influence of heredity and environment on bone density in young men. Another aim was to discover whether the same genetic factors influence bone mass, lean mass and muscle strength. Fifty families including a father, mother and one son were investigated. The mothers (aged 44.5 +/- 4.4 years) and fathers (aged 47.1 +/- 4.4 years) generally had a sedentary lifestyle with little physical activity. As a contrast, all but three of the sons (aged 17.0 +/- 0.4 years) were active in ice hockey training. Bone mineral density (BMD, g/cm2) of the total body, head, lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Muscle strength of the hamstrings and quadriceps muscles was also measured in the boys. BMD values of different sites in the fathers, mothers and sons were adjusted for weight, height, age, and any significant influence of environment. Heritability estimates were obtained as regression coefficients with the boys' adjusted BMD as dependent variable and the adjusted midparent bone density (father BMD + mother BMD/2) as independent variable. Accordingly, heritability explained 34-54% of the variation in the sons' BMD. Midparent BMD of several sites also predicted the boys' lean mass and quadriceps strength, and midparent-offspring differences in lean mass predicted midparent-offspring differences in BMD of the total body, head and spine (beta = 0.30-0.51, p < 0.05). The sons were found to have almost 30% higher femoral neck BMD than their fathers, and physical activity (hours/week) predicted BMD at several sites among the sons beta = 0.26-0.34, p < 0.05). In conclusion, heritability is a main determinant of the variance in BMD in young men. Based on the results we suggest that the same genetic factors may influence bone mass, lean mass and muscle strength by affecting body size. The present study also emphasizes the importance of physical activity for the development and maintenance of BMD in men.

Adolescent↗

PubMed2003

Long-term correction of glycogen storage disease type II with a hybrid Ad-AAV vector.

We administered an adenovirus-adeno-associated virus (Ad-AAV) vector encoding human acid alpha-glucosidase (hGAA) to acid alpha-glucosidase-knockout (GAA-KO) mice on day 3 of life by gastrocnemius injection. In contrast to previous results for muscle-targeted Ad vector in adult GAA-KO mice, the muscles of the hindlimb showed reduced glycogen content and persistent hGAA for as long as 6 months after neonatal Ad-AAV vector administration. Not only the injected gastrocnemius muscles, but also the hamstrings and quadriceps muscles produced therapeutic levels of hGAA as a result of widespread transduction with the Ad-AAV vector; moreover, hGAA activity was 50-fold elevated as compared to normal mice. Vector RNA was detected in the hindlimb muscles, the hearts, and the livers by northern blot analysis and/or by RT-PCR for as long as 6 months. The low levels of hGAA detected in the heart were attributable to transduction with the Ad-AAV vector, not to secretion of hGAA by the injected muscle and uptake by the heart. Finally, although an antibody response to hGAA was present, it did not prevent the correction of glycogen storage in the skeletal muscle of GAA-KO mice.

Adenoviridae↗

PubMed2004

Dysferlinopathy associated with rigid spine syndrome.

Dysferlinopathy and rigid spine syndrome occurring in a 50-year-old man is reported. The patient noticed stiffness of knee and ankle joints, which gradually extended to neck, wrist and elbow joints leading to difficulty in anterior flexion. Muscular weakness and wasting of the lower extremities had developed since age 40, accompanied by a limitation of anterior bending of the spine. Elevated serum CK was noticed. Muscle CT revealed atrophy with moderate fatty replacement of muscles in the neck, shoulder and pelvic girdle, and marked replacement in the para-vertebral muscles, posterior compartment of hamstrings and calf muscles. Electromyography showed a typical myogenic pattern, and muscle biopsy disclosed dystrophic changes, compatible with limb-girdle muscular dystrophy 2B. Loss of dysferlin expression was verified by immunohistochemistry, which was confirmed by a mini-multiplex Western blotting system. Gene analyses of the dysferlin gene disclosed compound heterozygotes for frameshift (G3016 + 1A) and a missense mutation (G3370T). This study might propose some clues to resolve the combination of musular dystrophies and rigid spine syndrome.

Dysferlin↗

PubMedDate not supplied

Exercise-related knee joint laxity.

Knee injuries are the topic of increasingly sophisticated research because of the importance in professional athletics as well as increasing participation in recreational sports. The role of conditioning and fatigue in these injuries remains controversial. Ligaments have high collagen content, and a viscoelastic response to stress would be expected. Because of the postulated relationship between laxity and knee ligament injuries, an experiment was designed using highly motivated athletes to test the hypothesis that exercise to the point of muscular fatigue may cause laxity of the knee and thereby place athletes at risk for ligamentous injury to the knee when fatigued. An exercise protocol was designed to produce muscle fatigue in the hamstring and quadriceps muscle groups. Knee ligament laxity was tested prior to and subsequent to the exercise protocol. To document muscle fatigue, isokinetic testing of right knee flexion and extension power was used several times during the exercise protocol. A knee arthrometer (KT-1000) was used to quantitatively document ligamentous laxity before and after exercise. The results indicated a significant lengthening in knee joint laxity between preexercise and postexercise in the left knee as measured at 15 and 20 pounds of passive displacement force (P less than 0.05). Maximum manual displacement also demonstrated a significant increase in joint laxity (P = 0.02). The right knee, which had undergone isokinetic testing, demonstrated a similar tendency but without a statistically significant difference before and after exercise. There was no significant preexercise side to side difference, but postexercise measurements demonstrated a left-right difference at 15 pounds, 20 pounds, and maximum manual displacement of statistical significance (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1997

Childhood-onset autosomal-dominant limb-girdle muscular dystrophy with cardiac conduction block.

We report childhood-onset autosomal-dominant limb-girdle muscular dystrophy (LGMD) in a Chinese family with complete atrioventricular conduction block in the adult members. Six patients, including 5 men and 1 woman with an age of onset from 3 to 7 years, were affected. The grandfather had exercise intolerance since childhood and complete heart block with pace-maker placement at age 52. Three siblings had proximal muscle weakness and/or wasting since age 5 and heart block in their 40s. Two grandsons at the ages 7 and 3 showed exercise intolerance, and proximal muscle weakness and wasting. Sinus bradycardia was present in the elder grandson. Muscle enzymes were elevated in 3, particularly in childhood. Muscle biopsies from the proband showed myopathic changes with fatty degeneration, whorled fibers, and rimmed vacuoles. In adult patients, muscle magnetic resonance imaging scans disclosed atrophic changes and fatty degeneration in the gluteal, quadriceps, adductors, hamstrings, gastrocnemius, and soleus muscles, while in child probands the early atrophic changes were seen in the gluteal and hamstrings muscles. We conclude that this distinct family is characterized by childhood-onset autosomal-dominant LGMD with heart block and that prevention of sudden death in these patients is important.

Adolescent↗

PubMed1999

[Pain in the sole of the foot. Differential diagnosis and therapy].

Plantar foot pain can be caused by a wide variety of diseases. To facilitate diagnosis and treatment differentiation of two entities is useful. The first group contains those painful disturbances that are due to mechanical overload, the second group has no relation to biomechanical problems. Tightness of the gastrocnemius muscles and hamstrings are the main factors leading to mechanical overload. Therefore, thorough evaluation of these muscles and treatment of shortening by stretching exercises is of paramount importance.

Diagnosis, Differential↗

PubMed1997

Electromyographic analysis of muscle fatigue in anterior cruciate ligament deficient knees.

The aim of this study was to detect possible differences in muscle fatigue and recovery of knee flexor and extensor muscles in patients with a deficient anterior cruciate ligament compared with patients with a normal anterior cruciate ligament. Surface electromyography of 15 patients with anterior cruciate ligament deficiency was performed while the muscles were under 80% of maximum isometric contraction, and after 1, 2, 3, and 5 minutes of rest. During the first 60 seconds of contraction, all muscles recorded significantly decreased mean power frequency and increased amplitude. The rate of decrease of mean power frequency was significantly greater in the injured quadriceps and normal hamstrings. All muscles except two recovered to the initial mean power frequency level after 1 minute of rest. All but two muscles in the injured and normal limb recorded an overshoot of mean power frequency during the recovery phase. This overshoot phenomenon also was seen for some muscles in the amplitude analysis. The findings confirm the fatigue state in all the muscles, suggest recruitment of more Type II fibers as the muscle fatigues, and show the physiologic adaptation of the quadriceps and hamstrings to anterior cruciate ligament insufficiency. The current study indirectly shows a dissociation between low intramuscular pH and mean power frequency during the recovery phase. It also indirectly suggests that the atrophied thigh muscles have fiber type composition similar to that of the normal side.

Adaptation, Physiological↗

PubMed2000

[Muscle involvement of Stormorken's syndrome].

We described two patients, a mother and daughter, of Stormorken's syndrome. The syndrome is characterized clinically by autosomal dominant inheritance, congenital miosis, thrombocytopenia, asplenia and muscle weakness. Both patients had bleeding tendency, ichthyosis of arms, and muscle weakness. The daughter additionally had short stature (146 cm), low body weight (32 kg) and muscle cramp. Neurological findings of the patients included migraine-like headache, cognitive dysfunction, limitation of upward and lateral gaze, and amydriasis. Femoral muscle MRI of the daughter demonstrated decreased volume with patchy high intensity areas in the hamstrings. A muscle biopsy from the daughter showed myogenic changes with muscle fiber necrosis and regeneration, variation in fiber size, tubular aggregates in approximately 5% of fibers, and fibrous tissue proliferation. Dystrophin, dystrophin-associated proteins and dysferlin were normally expressed. Although both patients had elevated creatine kinase levels and generalized muscle wasting, muscle weakness was mild with slow progression. A certain membrane defect in the platelet and muscle fiber might be responsible for the pathogenesis of this syndrome.

Adult↗

PubMed2001

Evaluation of a deformable musculoskeletal model for estimating muscle-tendon lengths during crouch gait.

The hamstrings and psoas muscles are often lengthened surgically in an attempt to correct crouch gait in persons with cerebral palsy. The purpose of this study was to determine if, and under what conditions, medial hamstrings and psoas lengths estimated with a "deformable" musculoskeletal model accurately characterize the lengths of the muscles during walking in individuals with crouch gait. Computer models of four subjects with crouch gait were developed from magnetic resonance (MR) images. These models were used in conjunction with the subjects' measured gait kinematics to calculate the muscle-tendon lengths at the body positions corresponding to walking. The lengths calculated with the MR-based models were normalized and were compared to the lengths estimated using a deformable generic model. The deformable model was either left undeformed and unscaled, or was deformed or scaled to more closely approximate the femoral geometry or bone dimensions of each subject. In most cases, differences between the normalized lengths of the medial hamstrings computed with the deformable and MR-based models were less than 5 mm. Differences in the psoas lengths computed with the deformable and MR-based models were also small (<3 mm) when the deformable model was adjusted to represent the femoral geometry of each subject. This work demonstrates that a deformable musculoskeletal model, in combination with a few subject-specific parameters and simple normalization techniques, can provide rapid and accurate estimates of medial hamstrings and psoas lengths in persons with neuromuscular disorders.

Biomechanical Phenomena↗

PubMed1994

Factors associated with hamstring injuries. An approach to treatment and preventative measures.

Following hamstring strain, rehabilitation is often prolonged and frustrating for the athlete and for the sports medicine clinician. Though the initial treatment of rest, ice, compression and elevation is accepted for muscle strains, no consensus exists for rehabilitation of hamstring muscle strains. This lack of agreement concerning rehabilitation of hamstring injury represents our lack of understanding of the mechanism of injury and the factors that contribute to hamstring strain. A hamstring rehabilitation model is proposed that is based on our current understanding of the aetiological factors that contribute to hamstring muscle strain. The influence and interaction of hamstring strength, flexibility, warm-up and fatigue are aetiological factors that should be addressed in the rehabilitation and prevention of hamstring strains. The rehabilitation model is, however, not without limitations and speculations. Further research is needed to clarify the etiological factors of hamstring strain and the efficacy of different rehabilitation protocols.

Exercise Therapy↗

PubMedDate not supplied

Compensatory muscle activity in the posterior cruciate ligament-deficient knee during isokinetic knee motion.

We performed electromyographic analyses in 12 patients with posterior cruciate ligament-deficient knees to compare electrical activity in the quadriceps, hamstring, and gastrocnemius muscles between the uninjured and involved limbs. Each patient performed concentric isokinetic knee motion at 30 and 60 deg/sec in both limbs separately. Torques in knee extension and flexion and surface electromyograms from the quadriceps, medial hamstring, and medial gastrocnemius muscles were simultaneously recorded. The uninjured limb served as a control for each patient. Before generation of flexion torque, the gastrocnemius muscle was electrically activated significantly earlier in posterior cruciate ligament-deficient knees than in uninjured knees at each velocity. However, we could not find any significant differences between the posterior cruciate ligament-deficient and uninjured knees in torque curves and electromyelograms of the quadriceps and hamstring muscles. This study suggests that early contraction of the gastrocnemius muscle may be a part of a compensatory mechanism in posterior cruciate ligament-deficient knees.

Adolescent↗

PubMed1998

Postural adjustments accompanying fast pointing movements in standing, sitting and lying adults.

The present study evaluated the effect of different positions, which varied in the amount of bodily support, on postural control during fast pointing movements. Fourteen adult subjects were studied in standing, various sitting and lying positions. Multiple surface electromyograms (EMGs) of arm, neck, trunk and upper leg muscles and kinematics were recorded during a standard series of unilateral arm movements. Two additional series, consisting of bilateral arm movements and unilateral arm movements with an additional weight, were performed to assess whether additional task-load affected postural adjustments differently in a sitting and standing position. Two pointing strategies were used--despite identical instructions. Seven subjects showed an elbow extension throughout the movements. They used the deltoid (DE) as the prime mover (DE group). The other seven subjects performed the movement with a slight elbow flexion and used the biceps brachii (BB) as the prime mover (BB group). The two strategies had a differential effect on the postural adjustments: postural activity was less and substantially later in the BB-group than in the DE group. Anticipatory postural muscle activity was only present in the DE group during stance. In all positions and task-load conditions the dorsal postural muscles were activated before their ventral antagonists. The activation rate, the timing and--to a lesser extent the amplitude of the dorsal muscle activity was position dependent. The position dependency was mainly found in the caudally located lumbar extensor (LE) and hamstrings (HAM) muscles. The EMG amplitude of LE and HAM was also affected by body geometry (trunk and pelvis position). Position and body geometry had only a minor effect on the activity of the neck and thoracic extensor muscles. This difference in behaviour of lower and upper postural muscles suggests that they could serve different postural tasks: the lower muscles being more involved in keeping the centre of mass within the limits of the support surface, and the upper ones in counteracting the reaction forces generated by movement onset. Increasing task-load by performing bilateral movements and--to a minor extent--during loaded unilateral movements affected the temporal and quantitative characteristics of the postural adjustments during standing and sitting in a similar way. The effect was present mainly during the early part of the response (within 100 ms after prime mover onset). This suggests that feedforward or anticipatory mechanisms play a major role in the task-specific modulation of postural adjustments.

Adaptation, Physiological↗