Ultrasonographic observations of the maturation of basic movements in guinea pig fetuses

Ultrasonography has not previously been used for studying fetal movements in precocial rodents. The objective of this study was to ultrasonographically determine the sequence of the appearance of basic movements in a guinea pig fetus. The research included eight guinea pig females carrying one fetus each. Fetal movements were observed for 10 minutes each day, from the 25th to 38th day of gestation. The time and sequence of the appearance of movements was observed as follows: whole body flexion (mean 27.6 SD ± 1.68), whole body extension (mean 28.1 SD ± 1.12), head flexion (mean 28.1 SD ± 1.80), head extension (mean 30.5 SD ± 2.67) forelimbs flexion (mean 30.5 SD ± 2.32), forelimbs extension (mean 30.7 SD ± 1.84), trunk rotation (mean 31.9 SD ± 2.23), forelimbs alternating flexion and extension (mean 32.1 SD ± 2.1), hind limbs extension (mean 32.2 SD ± 3.2), hind limbs flexion (mean 32.4 SD ± 3.16), and hind limbs alternating flexion and extension (mean 33.5 SD ± 2.39). The identical sequences of basic movement appearances in guinea pigs, sheep, and rats suggest that the rostrocaudal gradient of basic movement appearance could be a general developmental pattern in mammalian species.     

Comparison between subjective and ultrasound assessments of fetal movement.

Forty pregnant women participated in a study to compare subjective with ultrasound assessments of fetal movements. A real-time ultrasound scanner was used. Movements were recorded for 45 minutes in all cases. There was a significant positive correlation between the number of movements recorded by the two methods, but the 95% confidence limits were wide and no correlation was found in those patients who recorded fewer than 20 movements in the study period. Thus "false-positive" information may be obtained from purely subjective data, and in patients reporting low "kick counts" fetal activity should be assessed from real-time ultrasound recordings.     

The association between cardiac accelerations and movements in fetal sheep

Observations in 5 fetal sheep at 120-134 days gestation, using either real time ultrasound or direct emg recordings to detect fetal movements, showed an association between such movements and cardiac accelerations (greater than 2 s duration and 4 beats/min amplitude). Neuromuscular blockade with gallamine abolished the fetal movements but not the accelerations.     

Measurement of mandibular movements in patients with temporomandibular disorders and in asymptomatic subjects

The aim of the study was to investigate the range of mandibular movements and to analyze the difference in range of mouth opening, right and left lateral movements, and protrusive movement between patients with clinical diagnoses of temporomandibular disorders and asymptomatic subjects (control group) in a young male population. A total of 240 subjects, aged 19-28, were included in the study. The TMD sample comprised 180 patients (60 patients with muscle disorders; 60 patients with disc displacement with reduction; and 60 patients with muscle disorders and disc displacement with reduction) and was compared with 60 healthy control subjects. All participants were evaluated by the attending dentists at baseline by means of a physical examination of the masticatory system and a history questionnaire which included the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I measures. Analysis of variance (ANOVA) with the post hoc Bonferroni criteria showed significant difference in ranges of mandibular movements between and within the groups of asymptomatic subjects and TMD patients for active mouth opening (p = 0.001), right lateral movement (p = 0.002), left lateral movement (p = 0.006), and protrusive movement (p = 0.05). It has been found that there are statistically significant differences in the range of mandibular movements that separate asymptomatic subjects and patients with muscle disorders and disc displacements with reduction in this young male population. However, we cannot conclude that measurements of active mandibular movements can discriminate one group (TMD patients) from the other (asymptomatic subjects), because the mean ranges of these active movements between the groups were measured in clinically "normal" values.     

Dose comparison of ultrasonic transdermal insulin delivery to subcutaneous insulin injection

Prior studies have demonstrated the effectiveness of noninvasive transdermal insulin delivery using a cymbal transducer array. In this study the physiologic response to ultrasound mediated transdermal insulin delivery is compared to that of subcutaneously administered insulin. Anesthetized rats (350-550 g) were divided into four groups of four animals; one group representing ultrasound mediated insulin delivery and three representing subcutaneously administered insulin (0.15, 0.20, and 0.25 U/kg). The cymbal array was operated for 60 minutes at 20 kHz with 100 mW/cm2 spatial-peak temporal-peak intensity and a 20% duty cycle. The blood glucose level was determined at the beginning of the experiment and, following insulin administration, every 15 minutes for 90 minutes for both the ultrasound and injection groups. The change in blood glucose from baseline was compared between groups. When administered by subcutaneous injection at insulin doses of 0.15 and 0.20 U/kg, there was little change in the blood glucose levels over the 90 minute experiment. Following subcutaneous administration of insulin at a dose of 0.25 U/kg, blood glucose decreased by 190 +/- 96 mg/dl (mean +/- SD) at 90 minutes. The change in blood glucose following ultrasound mediated insulin delivery was -262 +/- 40 mg/dl at 90 minutes. As expected, the magnitude of change in blood glucose between the three injection groups was dependant on the dose of insulin administered. The change in blood glucose in the ultrasound group was greater than that observed in the injection groups suggesting that a higher effective dose of insulin was delivered.     

European Society of Biomechanics S.M. Perren Award 2018: Altered biomechanical stimulation of the developing hip joint in presence of hip dysplasia risk factors

Fetal kicking and movements generate biomechanical stimulation in the fetal skeleton, which is important for prenatal musculoskeletal development, particularly joint shape. Developmental dysplasia of the hip (DDH) is the most common joint shape abnormality at birth, with many risk factors for the condition being associated with restricted fetal movement. In this study, we investigate the biomechanics of fetal movements in such situations, namely fetal breech position, oligohydramnios and primiparity (firstborn pregnancy). We also investigate twin pregnancies, which are not at greater risk of DDH incidence, despite the more restricted intra-uterine environment. We track fetal movements for each of these situations using cine-MRI technology, quantify the kick and muscle forces, and characterise the resulting stress and strain in the hip joint, testing the hypothesis that altered biomechanical stimuli may explain the link between certain intra-uterine conditions and risk of DDH. Kick force, stress and strain were found to be significantly lower in cases of breech position and oligohydramnios. Similarly, firstborn fetuses were found to generate significantly lower kick forces than non-firstborns. Interestingly, no significant difference was observed in twins compared to singletons. This research represents the first evidence of a link between the biomechanics of fetal movements and the risk of DDH, potentially informing the development of future preventative measures and enhanced diagnosis. Our results emphasise the importance of ultrasound screening for breech position and oligohydramnios, particularly later in pregnancy, and suggest that earlier intervention to correct breech position through external cephalic version could reduce the risk of hip dysplasia.     

Effect of male accessory glands autoaggression on androgenic cytosolic and nuclear receptors of rat prostate.

The effect of immunization against male accessory gland (MAG) homogenates over androgenic cytosolic and nuclear receptors of rat prostate was studied. In the MAG-immunized rats the Bmax of cytosolic receptors was significantly increased (120.3 +/- 44.3 vs 47.7 +/- 24.9 fmol/mg protein, p less than 0.01, mean +/- SD). In contrast, the Bmax of nuclear receptors in the MAG-immunized rats showed no significant difference as regarded controls (kidney immunized rats) when expressed as fmol/100 micrograms DNA (196.1 +/- 84.8 vs 148.3 +/- 88.9) but it show to slight differences (p less than 0.1) when data were reported as percent of weight of tissue (2,189 +/- 918.6 vs 1,303 +/- 611.2 fmol/g wet issue). Results (mean +/- SD) on binding affinity of cytosolic receptors showed no significant differences in MAG-immunized rats as compared with controls (Kd: 1.98 +/- 0.66 vs 1.92 +/- 0.20 nM). Likewise, only a slight difference between both groups was attained for Kds of nuclear receptors (2.34 +/- 0.28 vs 1.80 +/- 0.62 nM, p less than 0.2). On the other hand, 5 alpha 1-dihydrotestosterone (DHT) values obtained in prostate homogenates were significantly decreased in MAG-immunized rats as compared with controls (17.4 +/- 2.0 vs 7.1 +/- 0.9 ng/g tissue, mean +/- SD, p less than 0.01). However, testosterone (T) levels in gland tissue showed no significant differences between both groups (2.4 +/- 0.5 vs 2.6 +/- 0.3 ng/g tissue) with an increase in the T: DHT ratio from 0.14 to 0.37.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maternal perception of fetal motor activity.

A technique using real-time ultrasound for comprehensive recording of fetal motor activity was used in 20 subjects in the third trimester of pregnancy. Maternal awareness of fetal movement correlated with the number of fetal parts contributing to the movement but not with maternal parity or obesity, gestational age, placental site, or duration of the fetal movement. Some subjects recorded fetal breathing, passive fetal displacement, and Braxton Hicks''s contractions as fetal movement. Most of our subjects were consistent and accurate in their perception of major fetal movements, but a few were inconsistent and one was completely unaware of major fetal movements. These results suggest that kick counts kept by most mothers will be accurate. Low counts of fetal movement should be an indication for fetal monitoring by other means and not, unconfirmed, for intervention.     

Mechanism of transient nocturnal hypoxemia in hypoxic chronic bronchitis and emphysema

In five patients with hypoxic chronic bronchitis and emphysema we measured ear O2 saturation (SaO2), chest movement, oronasal airflow, arterial and mixed venous gas tensions, and cardiac output during nine hypoxemic episodes (HE; SaO2 falls greater than 10%) in rapid-eye-movement (REM) sleep and during preceding periods of stable oxygenation in non-REM sleep. All nine HE occurred with recurrent short episodes of reduced chest movement, none with sleep apnea. The arterial PO2 (PaO2) fell by 6.0 +/- 1.9 (SD) Torr during the HE (P less than 0.01), but mean arterial PCO2 (PaCO2) rose by only 1.4 +/- 2.4 Torr (P greater than 0.4). The arteriovenous O2 content difference fell by 0.64 +/- 0.43 ml/100 ml of blood during the HE (P less than 0.05), but there was no significant change in cardiac output. Changes observed in PaO2 and PaCO2 during HE were similar to those in four normal subjects during 90 s of voluntary hypoventilation, when PaO2 fell by 12.3 +/- 5.6 Torr (P less than 0.05), but mean PaCO2 rose by only 2.8 +/- 2.1 Torr (P greater than 0.4). We suggest that the transient hypoxemia which occurs during REM sleep in patients with chronic bronchitis and emphysema could be explained by hypoventilation during REM sleep but that the importance of changes in distribution of ventilation-perfusion ratios cannot be assessed by presently available techniques.     

The effect of warm-up on high-intensity, intermittent running using nonmotorized treadmill ergometry

The aim of this study was to investigate the effect of previous warming on high-intensity intermittent running using nonmotorized treadmill ergometry. Ten male soccer players completed a repeated sprint test (10 x 6-second sprints with 34-second recovery) on a nonmotorized treadmill preceded by an active warm-up (10 minutes of running: 70% VO2max; mean core temperature (Tc) 37.8 +/- 0.2 degrees C), a passive warm-up (hot water submersion: 40.1 +/- 0.2 degrees C until Tc reached that of the active warm-up; 10 minutes +/- 23 seconds), or no warm-up (control). All warm-up conditions were followed by a 10-minute static recovery period with no stretching permitted. After the 10-minute rest period, Tc was higher before exercise in the passive trial (38.0 +/- 0.2 degrees C) compared to the active (37.7 +/- 0.4 degrees C) and control trials (37.2 +/- 0.2 degrees C; p < 0.05). There were no differences in pre-exercise oxygen consumption and blood lactate concentration; however, heart rate was greater in the active trial (p < 0.05). The peak mean 1-second maximum speed (MxSP) and group mean MxSP were not different in the active and passive trials (7.28 +/- 0.12 and 7.16 +/- 0.10 m x s(-1), respectively, and 7.07 +/- 0.33 and 7.02 +/- 0.24 m x s(-1), respectively; p > 0.05), although both were greater than the control. The percentage of decrement in performance fatigue was similar between all conditions (active, 3.4 +/- 1.3%; passive, 4.0 +/- 2.0%; and control, 3.7 +/- 2.4%). We conclude that there is no difference in high-intensity intermittent running performance when preceded by an active or passive warm-up when matched for post-warm-up Tc. However, repeated sprinting ability is significantly improved after both active and passive warm-ups compared to no warm-up.     

Effects of hyperthermia on fetal breathing movements

High environmental temperature is known to impair fetal growth and development. We now report long lasting changes in fetal breathing activity following the exposure of pregnant ewes to an ambient temperature of 43 degrees C for 8 h. In 16 trials in 10 ewes (119-138 days gestation) heat exposure increased maternal and fetal core temperatures 1.5-2.0 degrees C, and the hyperventilation by the ewe produced a fall in fetal PaCO2 from 53.5 +/- 1.3 to 34.8 +/- 5.3 mmHg (P less than 0.05). Fetal breathing movements decreased in incidence during the hyperthermia but remained episodic (present during low-voltage electrocortical activity) with occasional brief episodes of breathing at high rates (greater than 4 breaths/s). However, 1-2 h after the end of heating, when maternal and fetal core temperature and PaCO2 had returned to normal, fetal breathing movements became continuous, and were augmented 30-100% in amplitude. Fetal breathing movements occurred during both low- and high-voltage electrocortical activity. The results show that a heat load similar to that experienced by sheep in sub-tropical regions in the summer months cause prolonged changes in the central regulation of fetal breathing.     

Significantly decreased apparently free testosterone levels in plasma of male homosexuals.

Total and free plasma testosterone (T) were determined in male homosexuals. While total T showed no significant difference to a heterosexual control group, apparently free T in plasma was significantly lower (p less than 0.001) in 35 male homosexuals (mean +/- SD = 10.7 +/- 3.3 ng/100 ml) than in 38 male heterosexuals of similar age (13.3 +/- 4.5 ng/100 ml).     

Central serotonin receptors and delayed gastric emptying in non-ulcer dyspepsia.

OBJECTIVE--To determine whether central serotonin receptors are involved in the pathophysiology of non-ulcer dyspepsia. DESIGN--Between subjects study of solid phase gastric emptying and prolactin response to buspirone challenge. SUBJECTS--12 patients fulfilling criteria for non-ulcer dyspepsia and 12 age and sex matched controls. MAIN OUTCOME MEASURES--Solid phase gastric emptying measured by scintigraphic assessment of the movement of a standard meal labelled with technetium-99m and indium-111; responsiveness of central serotonin 1A receptors measured by the prolactin release following challenge with oral buspirone 60 mg. RESULTS--Solid phase gastric emptying was significantly delayed in the patients with non-ulcer dyspepsia (t 1/2 = 90.6 (SD 14.5) minutes in patients and 54.6 (10.7) minutes in controls; 95% confidence interval 24.7 to 46.7 minutes, p < 0.001). Prolactin release was significantly greater in patients compared with controls (1272.7 (1039.9) mU/l v 292.9 (136.1) mU/l; 352.1 to 1607.5 mU/l, p < 0.01). Gastric emptying and prolactin release were significantly correlated (r = 0.59, p = 0.04) in the patients but not in the controls (r = 0.23). CONCLUSION--Central serotonin 1A receptors may have a role in the pathophysiology of non-ulcer dyspepsia of the dysmotility subtype.     

Assessing the Perception of Trunk Movements in Military Personnel with Chronic Non-Specific Low Back Pain Using a Virtual Mirror

Chronic pain, including chronic non-specific low back pain (CNSLBP), is often associated with body perception disturbances, but these have generally been assessed under static conditions. The objective of this study was to use a “virtual mirror” that scaled visual movement feedback to assess body perception during active movement in military personnel with CNSLBP (n = 15) as compared to military healthy control subjects (n = 15). Subjects performed a trunk flexion task while sitting and standing in front of a large screen displaying a full-body virtual mirror-image (avatar) in real-time. Avatar movements were scaled to appear greater, identical, or smaller than the subjects’ actual movements. A total of 126 trials with 11 different scaling factors were pseudo-randomized across 6 blocks. After each trial, subjects had to decide whether the avatar’s movements were “greater” or “smaller” than their own movements. Based on this two-alternative forced choice paradigm, a psychophysical curve was fitted to the data for each subject, and several metrics were derived from this curve. In addition, task adherence (kinematics) and virtual reality immersion were assessed. Groups displayed a similar ability to discriminate between different levels of movement scaling. Still, subjects with CNSLBP showed an abnormal performance and tended to overestimate their own movements (a right-shifted psychophysical curve). Subjects showed adequate task adherence, and on average virtual reality immersion was reported to be very good. In conclusion, these results extend previous work in patients with CNSLBP, and denote an important relationship between body perception, movement and pain. As such, the assessment of body perception during active movement can offer new avenues for understanding and managing body perception disturbances and abnormal movement patterns in patients with pain.     

Hemodynamics of the lower extremity with pneumatic foot compression. Effect on leg position]

External pneumatic compression of the foot is being used more and more to increase the venous blood flow in the lower limbs and thus reduce the risk of postoperative deep venous thrombosis. We have investigated the efficacy of the foot pump pneumatic compression device (A-V Impulse, Novamedix, Andover, England) in 10 healthy subjects and in 10 patients undergoing total hip arthroplasty. The velocity of venous blood flow in the common femoral artery was measured in the horizontal, Trendelenburg (head-down, foot-up) and reverse Trendelenburg (head-up and foot-down) positions using a duplex ultrasound unit (Sonoline Elegra, Siemens, Erlangen, Germany) with a 5 MHz linear array probe. Application of the foot pump produced an increase in venous blood flow velocity in all healthy subjects and in all patients. In healthy subjects the mean increase in the horizontal position was 31.18% (SD = 15.86%), and in the Trendelenburg position 20.72 (SD = 15.69%) (right limb). In the reverse Trendelenburg position, the foot pump produced a mean increase of 94.08% (SD = 55.00%). The difference is statistically significant (p < 0.005). In patients with a total hip arthroplasty, the mean increase in the horizontal position was 28.67% (SD = 9.95%), and in the Trendelenburg position 20.34% (SD = 17.85%) (operated limb). In the reverse Trendelenburg, the foot pump produced a mean increase of 91.55% (SD = 42.38%). The difference is statistically significant (p < 0.005). There was no noteworthy difference in results between the controls and patients. Pneumatic compression devices designed to reduce venous stasis are effective in decreasing the rate of deep venous thrombosis after surgery on the lower limb. The results of the present study show that the efficiency of the foot pump in increasing venous return is improved by adopting the reverse Trendelenburg position. This may increase its thromboprophylactic effect.     

Risk of minor and major fetal malformations in diabetics with high haemoglobin A1c values in early pregnancy.

Maternal haemoglobin A1c (HbA1c) values were measured before the end of the 15th week of gestation in 142 pregnancies in women with insulin dependent diabetes. In pregnancies complicated by fetal malformations (n = 17) the mean initial HbA1c value was 9.5 (SD 1.8)% of the total haemoglobin concentration, which was significantly (p less than 0.001) higher than in pregnancies without malformations (8.0 (SD 1.4)%; n = 125). HbA1c values did not differ between pregnancies complicated by minor and major fetal malformations, but the rate of malformations showed a positive relation to the HbA1c value in early pregnancy (chi 2 = 11.9; p = 0.001). Fetal malformations occurred in six out of 17 pregnancies (35.3%) in mothers whose initial HbA1c value was 10% or more, in eight out of 62 pregnancies (12.9%) in mothers with initial values between 8.0% and 9.9%, and in only three out of 63 pregnancies (4.8%) in mothers with an initial value below 8.0%. These data support the hypothesis that the increased incidence of fetal malformations in mothers with insulin dependent diabetes is associated with maternal hyperglycaemia during organogenesis. Hence diabetic women who are planning to have a child--especially those with a high HbA1c value--should receive intensified metabolic control.     

Humoral immune response to Malassezia furfur in patients with pityriasis versicolor and seborrheic dermatitis

Humoral immune responses against exoantigen components of oval, elliptic and round yeast forms of Malassezia furfur were analysed by ELISA and Western blotting assays, using sera from patients with pityriasis versicolor (PV), seborrheic dermatitis (SD) and healthy adults (HA), as control. Sera from patients with SD showed IgG anti-oval M. furfur titers ranging from 1/400 to 1/6400 showing geometric mean (GM) of 1/1472, higher than those obtained with sera from patients with PV (1/200 to 1/6400, GM = 1/1239). Both patient groups showed mean titres statistically superior (p < 0.05) than those obtained from HA (GM = 1/229). Similar data were also obtained with the elliptic and round antigens. However, the anti-oval IgG mean titers from patients' sera were much higher than those obtained with elliptic or round antigenic components (p < 0.05). Anti-M. furfur IgM titers obtained from patient's sera with PV against all three exoantigens were statistically superior (p < 0.05) than HA group. Patients with SD showed IgM titers statistically superior (p < 0.05) only to oval yeasts of M. furfur. The IgA mean titers from patients' groups against the different morphological antigens were shown be slightly higher than those HA group. By Western blot, using rabbit anti-sera, the different antigenic components of M. furfur showed a close relationship mainly between oval and elliptic yeast cells antigens. The 70 kDa component of the M. furfur exoantigen of oval morphology was recognized by 84% of the PV patients' sera. On the other hand, SD patients' sera recognized 3 principal components of 70 kDa (100%), 65 kDa (67%) and 84 kDa (53%). These components may be considered immunological markers for PV and SD. Twenty-five percent of HA sera recognized the components of 65, 70 and 94 kDa. This investigation shows that M. furfur antigens can sensitize the host, mainly the oval yeast form of M. furfur with a very important specific IgG response in patients with SD and PV. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biomechanical comparison of unilateral and bilateral power snatch lifts

Biomechanical characteristics of the one-handed dumbbell power snatch (DBPS) were examined to determine whether significant differences existed between unilateral and bilateral weightlifting movements. Kinetic and kinematic movement data were recorded from 10 male weightlifters (mean +/- SD: age: 30.2 +/- 10.2 years; height: 174.2 +/- 4.4 cm; body mass: 81.5 +/- 14.6 kg) during one-handed dumbbell (DB) and traditional barbell (BBPS) power snatch performance with loads of approximately 80% of respective lift one repetition maximums (1RM) with the use of 2 synchronized Kistler force plates and high-speed 3-dimensional video. Results highlighted asymmetry in the ground reaction force and kinematic profile of the DBPS, which deviated from the observed patterns of the bilateral movement. This study found that the nonlifting side (the side corresponding with the hand that did not hold the DB) tended to generate a greater pull phase peak vertical ground reaction forces significantly faster (p = 0.001) than the lifting side (the side corresponding with the hand that held the DB) during the DBPS. In addition, the DBPS nonlifting side catch phase loading rate was approximately double that of the lifting side loading rate (p < 0.05). These results quantify symmetrical deviations in the movement patterns of the unilateral power snatch movement both during the concentric muscular contraction of load vertical displacement, and the loading implications of unilateral landing. This asymmetry supports the contention that unilateral variations of weightlifting movements may provide a different training stimulus to athletes.     

Effects of yohimbine on bradycardia and duration of recumbency in ketamine/xylazine anesthetized ferrets

Eleven adult ferrets (Mustela putorius furo) were anesthetized with ketamine hydrochloride (25 mg/kg, IM) and xylazine hydrochloride (2 mg/kg, IM). Fifteen minutes post-ketamine/xylazine injection, ferrets were treated with yohimbine hydrochloride at a dose of 0.5 mg/kg, or an equal volume of physiologic saline, intramuscularly. Each ferret served as its own control by randomly receiving both treatments with a minimum interval of 2 weeks between treatments on any one ferret. At 15 minutes post-ketamine/xylazine injection, mean heart rate measurements for both treatment groups were 27% less than the mean heart rate measurement reported for unanesthetized ferrets. Intramuscular administration of yohimbine antagonized the ketamine/xylazine induced bradycardia in 10 of the 11 ferrets, (p = 0.0001). In yohimbine treated ferrets, an increase in mean heart rate measurement was noted 5 minutes after the intramuscular administration of yohimbine, and followed, over the next 15 minutes, by a progressive increase in mean heart rate. However, a corresponding decrease in mean heart rate measurement was observed in saline treated controls. Fifteen minutes after the injection of yohimbine, the mean heart rate measurement of yohimbine treated animals had increased to 194 beats per minute. This mean heart rate measurement is nearly 30% greater than the mean heart rate of 150 beats per minute measured at 15 minutes post-saline injection in saline treated controls. Also, yohimbine treatment significantly reduced duration of recumbency in 10 of 11 ferrets (p = 0.0001). Mean duration of recumbency for yohimbine treated ferrets was 41 +/- 9.7 minutes, whereas mean duration of recumbency for saline treated ferrets was determined to be 80 +/- 11.4 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics and lateral dominance of hand grip and elbow flexion powers in young male adults

This study aimed to clarify the characteristics and the lateral dominance of hand grip power and elbow flexion power. The subjects were 15 healthy young males (mean age 22.1+/-0.7 yr, mean height 171.3+/-3.4 cm, mean mass 64.5+/-4.1 kg). All subjects were right-handed. Peak power was measured by both hands with 6 different loads of 20%-70% of maximum voluntary contraction. The maximum voluntary contraction of hand grip movement and elbow flexion movement was significantly larger in the dominant hand. Peak power of the dominant hand was larger in all loads in hand grip movement and in loads of 20% and 30% of maximum voluntary contraction in elbow flexion movement. In short, lateral dominance was confirmed. Peak power was significantly larger in hand grip movement than in elbow flexion movement in both hands. Peak velocity decreased with increasing loads in both movements, but peak power increased until about 50% of maximum voluntary contraction and then decreased. The peak power ratio of the dominant hand to the nondominant hand was significantly larger in hand grip movement than in elbow flexion movement in all loads and the peak power ratio in elbow flexion movement was more marked in light loads. In conclusion, both powers showed lateral dominance. Lateral dominance is more marked in hand grip power.