Arm Movement Frequencies Research Articles

Changing coupling between the arms and legs with slow walking speeds alters regulation of somatosensory feedback

Arm swing movement is coordinated with movement of the legs during walking, where the frequency of coordination depends on walking speed. At typical speeds, arm and leg movements, respectively, are frequency locked in a 1:1 ratio but at slow speeds this changes to a 2:1 ratio. It is unknown if the changes in interlimb ratio that accompany slow walking speeds alters regulation of somatosensory feedback. To probe the neural interactions between the arms and legs, somatosensory linkages in the form of interlimb cutaneous reflexes were examined. It was hypothesized that different interlimb frequencies and walking speeds would result in changes in the modulation of cutaneous reflexes between the arms and legs. To test this hypothesis, participants walked in four combinations of walking speed (typical, slow) and interlimb coordination (1:1, and 2:1), while cutaneous reflexes and background muscle activity were evaluated with stimulation applied to the superficial peroneal nerve at the ankle and superficial radial nerve at the wrist. Results show main effects of interlimb coordination and walking speed on cutaneous reflex modulation, effects are largest in the swing phase, and a directional coupling was observed, where changes in the frequency of arm movements had a greater effect on muscle activity in the legs compared to the reverse. Task-dependent modulation was also revealed from stimulation at local and remote sources. Understanding the underlying neural mechanisms for the organization of rhythmic arm movement, and its coordination with the legs in healthy participants, can give insight into pathological walking, and will facilitate the development of effective strategies for the rehabilitation of walking.

Differences in coordination and timing of pre-reaching upper extremity movements may be an indicator of cerebral palsy in infants with stroke: A preliminary investigation

BackgroundNeonatal stroke is a leading cause of hemiplegic cerebral palsy that occurs around the time of birth. Infants are diagnosed with cerebral palsy when motor impairments become clinically apparent, months or years after the stroke. Tools/methods for identifying high risk or diagnosis of cerebral palsy in infancy are improving. MethodsWe measured spatial and temporal kinematics of pre-reaching upper extremity movements in 2–3 month old infants with neonatal stroke and typical development. We aimed to evaluate the feasibility of applying kinematics in this population and collect preliminary data to explore (1) if asymmetries are present in the infants with neonatal stroke, particularly those with a later diagnosis of cerebral palsy, and (2) to compare differences in the timing and coordination of their movements to infants with typical development, and infants with stroke and no cerebral palsy. Participants were 21 full-term infants, 10 with stroke (4 who later received a cerebral palsy diagnosis) age 72.1 (SD 9.3) days, and 11 typically developing, age 74.3 (SD 9.3) days. FindingsResults showed that infants with stroke and cerebral palsy demonstrated significant asymmetry in the average movement length (p = 0.0089) and hand path length (p = 0.0275) between their involved and uninvolved sides and moved less frequently (p = 0.09) and slower (p = 0.041) than infants with stroke and no cerebral palsy. InterpretationResults suggest that kinematic analysis might detect asymmetries and motor impairment indicative of hemiplegic cerebral palsy earlier than current assessments and that asymmetry in speed, length and frequency of arm movements may be early indicators. This study is preliminary, limiting interpretation of the results.

Strength Abilities: Overview of Development in Middle School Boys

The purpose of the study is to identify the peculiarities of strength preparedness of middle-school-aged boys. Materials and methods. The participants in the study were boys of sixth grade (n=36), seventh grade (n=36), eighth grade (n=33). The study used analysis and summary of scientific and methodological literature, pedagogical testing and methods of mathematical statistics for processing study results. The IBM SPSS 23 statistical analysis software was used to process the study materials. The following parameters were calculated: arithmetic mean value (X); standard deviation (s). The probability of difference in statistical indicators was estimated using the Student’s t-test. Results. The analysis of the results suggests that the sixth- and seventh-grade boys have statistically significant differences in the set of tests (p <0.05). The seventh-grade boys show the increase in strength indicators of the shoulder girdle muscles, abdominal and back muscles, leg muscles. The sixth- and eighth-grade boys show statistically significant differences in the set of tests (p<0.05). The eighth-grade boys demonstrate the increased indicators of strength and strength endurance of the shoulder girdle muscles, abdominal and back muscles, and leg muscles. There are also statistically significant differences in the test on frequency of arm movements (p<0.001) and in the “Standing long jump” (p<0.001). The seventh- and eighth-grade boys show statistically significant increase in strength indicators of the shoulder girdle muscles, the indicators of strength endurance of the abdominal and back muscles, and the indicators of strength endurance of the leg muscles. There are statistically significant differences in the test on frequency of arm movements (p<0.05) and in the “Shuttle run 4×9” (p<0.001). Conclusions. The middle-school-aged boys show a positive dynamics in the development of motor preparedness. The largest increase is observed in the indicators of strength and strength endurance of the shoulder girdle muscles, abdominal, back, and leg muscles.

Phase Manipulation and Walking in Stroke

The purpose of this study was to investigate the effects of in- and out-phase arm movement on upper and lower body movement patterns during walking in individuals with stroke. Eight individuals (ages 14-74 years) who had suffered a cerebrovascular accident and walked independently participated. There were three separate conditions of walking at 0.22, 0.40, and 0.63 m/s: (1) with no upper extremity phase manipulation, (2) instructions to move the arms in-phase at each velocity level, (3) instructions to move the arms out-of-phase at each velocity level. With instruction to the move the arms out-of-phase, the arms moved more reciprocally, back and forth, coinciding with increased arm swing, greater transverse trunk rotation as compared to when subjects were instructed to move the arms in-phase. Instructions to move the arms either in- or out-of-phase led to coordination between arm movement frequency and stride frequency (1:1 frequency coordination). Stroke is the leading cause of disability in the United These findings showed that altered arm swing is constrained by an attraction to 1:1 frequency coordination. Arm swing amplitude was not specified; however participants swung their arms at a frequency that synchronized with stride frequency (1:1 coordination). Future study is still needed to examine how paretic arm movement affects intersegmental coordination during walking. Research is needed to assess the effects of imposed upper extremity phasing and whether training with specific phase relations facilitates a relatively permanent change in the intersegmental coordination and therefore walking function in patients who have suffered a stroke.

Degree of Coordination between Breathing and Rhythmic Arm Movements During Hand Rim Wheelchair Propulsion

This study aimed (i) to quantify the spontaneous coordination between breathing and hand rim wheelchair propulsion, (ii) to manipulate arm movement frequency and assess its effects on spontaneous coordination, and (iii) to investigate the hypothesis that entrainment of breathing improves economy of locomotion and leads to a lower rate of perceived exertion (RPE) compared with spontaneous breathing. Nine male, able-bodied participants completed four bouts of 6 min submaximal steady state exercise at 60 % of maximal propulsion velocity on a wheelchair ergometer, with spontaneous breathing and arm frequencies (Fspont), with 20 % higher and lower arm frequencies (F +20 and F -20, respectively) compared to Fspont accompanied with spontaneous breathing frequency, and by synchronising expiration phase with pushing time and inspiration phase with upper limb recovery time (C). Oxygen uptake and propulsion frequency were continuously recorded. The degree of coordination was expressed as a percentage of inspiration starting in the same phase of the wheelchair propulsion cycle (i.e. pushing and recovery times). No difference in degree of coordination was observed between Fspont, F -20 and F +20 conditions (49.2 +/- 12.1 %, 49.1 +/- 29.0 % and 48.2 +/- 29.4 %, respectively). Oxygen uptake increased significantly during C condition while RPE was significantly lower for C and F -20 (p < 0.05) compared to F +20 conditions. Contrary to what we expected, entrainment of breathing using a monofrequency ratio (C) induced a higher energy cost probably due to the mechanical properties of the wheelchair propulsion activity itself. In conclusion, this study showed that the same locomotor-respiratory coupling occurred during hand rim wheelchair propulsion regardless of the arm movement frequency, and that entrainment of breathing did not improve economy of locomotion.

UPPER EXTREMITY PHASE MANIPULATION and WALKING IN PERSONS WITH A CVA.

Purpose/Hypothesis: To investigate the effects of walking velocity and upper extremity phase manipulation on inter-segmental coordination during treadmill walking in persons with a CVA. Number of Subjects: 8 individuals (12 – 72 yrs; mean 49; standard deviation: 17.4) who have suffered a CVA participated. Materials/Methods: There were 3 separate conditions while walking at 0.22, 0.40, 0.63, 0.85, 1.10, 1.30, and 1.52 m/s: 1) no upper extremity phase manipulation; 2) instructions to move the arms in phase at each velocity level; 3) instructions to move the arms out of phase at each velocity level. 3D kinematic data were collected using a Skill Technologies 6D Research System. The total range of movement amplitudes for arms (τA) and legs (τL), and transverse rotation of thorax (τT), pelvis (τP) was calculated. The amplitude of transverse trunk rotation (τPT) was calculated by determining the maximum differences between (τT) and (τP). The shoulder and hip angle time-series data were used to compute the point estimates of relative phase between the arms. We determined if the power (power spectrum) in arm movement frequency was higher at stride or step frequency during walking. For statistical analysis a within-group analysis of variance with repeated measures, including two within-factors, 1) velocity manipulation and 2) instruction was used with a .05 significance level. Results: Across all walking velocities the arms moved more out of phase during no upper extremity phase manipulation and instruction to move the arms out of phase, as compared to instruction to move the arms in phase. Instructions to move both in or out of phase, led to larger involved arm movement amplitude (τAi) and non-involved arm movement amplitude (τAni) as compared to the condition with no upper extremity phase manipulation. When participants were instructed to move the arms in phase the τAi was larger at both 0.43 and 0.66 m/s, as compared to instructions to move out of phase. The larger τAni coincided with the power in the non-involved arm movement frequency being higher at stride frequency when participants were instructed to move their arms in phase as compared to out of phase. Finally, τT, τP, and τPT were greater when participants were instructed to move their arms out of phase, as compared to in phase. Conclusions: The results from the present study demonstrate flexibility of the coordination patterns of walking to meet constraints imposed on the movements of body segments. Additionally, these results suggest that the ability to modify arm movement amplitude, along with frequency, is necessary for synchronization with the stride frequency. Clinical Relevance: Slower walking velocity in patients with severe upper extremity dysfunction (e.g., CVA) may be due to inability to alter coordination patterns. Future studies should investigate the underlying dynamics of arm dysfunction and adaptations during treadmill and over-ground walking. This will provide a foundation for interventions which address motor impairments of the upper and lower extremity related to walking in persons with a CVA.

Postural coordination patterns associated with the swinging frequency of arms

Voluntary arm movements frequently perturb body equilibrium in an upright posture. The motions of leg joints need to be coordinated according to the properties of voluntary arm movements in order to maintain body equilibrium, and this may cause a change in postural pattern. The purpose of this study was to determine whether the kinematic pattern generation of upright posture is influenced by a change in the swinging frequency of arm movements and whether the pattern generation is correlated with a change in joint torque about the shoulder joint. Four male subjects in an upright posture were instructed to swing their arms at seven different frequencies, determined by the maximum swinging frequency of each subject (35%max, 40-60%max, 65%max). Segment rotations around the shoulder, hip, and ankle joints were analyzed at kinematic and kinetic levels. The results of kinematic analysis indicated that tight coupling between motions of the shoulder and hip joints was generated in lower-frequency trials (under 40-45%max), whereas tight coupling between motions of the shoulder and ankle joints was generated in higher frequency trials (more than 40-45%max). Furthermore, the results of kinetic analysis revealed that changes in the joint torque patterns about the shoulder and hip joints occurred in trials at 40-45%max. The mean value of 40-45%max was close to the eigenfrequency of each subject's arm. We concluded that (1) postural patterns associated with a gradual change in the swinging frequency of the arms can be divided into two coordination modes (a hip-shoulder in-phase mode and an ankle-shoulder in-phase mode), and (2) these two patterns may be divided by the eigenfrequency of the arm.

Human development of grip force modulation relating to cyclic movement-induced inertial loads.

The present study examines the development of grip force modulation relating to self-induced loads during repetitive vertical arm movements at different frequencies with a hand-held object. One hundred and thirty-four 3- to 6-year-old children and 16 adults were asked to move a lightweight object up and down at increasing rates from 0.5 Hz up to individual maximal arm movement rates (> 2.5 Hz). Grip forces were measured by a uni-axial force transducer and the inertial forces (tangential forces) were calculated from the measurements by accelerometers within the object. Generally, the quality of anticipatory grip force control improved from movement frequencies of 1 Hz to 2.5 Hz and decreased above 2.5 Hz. At movement frequencies below 1 Hz, the phase lag between grip and load force cycles was longer in children than in adults (children: median = 17 ms; adults: median = 0 ms); however, there were no significant differences between the age groups above 1.5 Hz. The grip-to-load force ratio and the grip force modulation were not significantly different from the adults up to 2.5 Hz. The fine coupling of grip and load forces (precise temporal and gain control) showed age effects among the 3- to 6-year-old children, mainly between 3- and 4-year-olds, and in adults extremely good coupling at medium arm movement frequencies. However, concerning the pure temporal coordination of grip and inertial forces, there were only differences between the 3-year-old children and the other groups at arm movement frequencies above 2.5 Hz. The results show that, during cyclic movements with hand-held loads, temporal control is well established at the age of 4 years whereas the fine gain control needs a longer time to develop. The anticipatory control is dependent on the arm movement frequency and, therefore, how rapidly the inertial loads change. The high level of anticipatory control during self-induced repetitive actions in children of 3-6 years of age is interpreted as an early developing ability to predict precisely cyclic self-induced inertial loads of hand-held objects when the object properties are known by proprioception. The timing, which is possibly related to cerebellar functions, is, to some extent, developed earlier than the gain control, which may be associated with cortical functions.

Resonant frequencies of arms and legs identify different walking patterns

The present study is aimed at investigating changes in the coordination of arm and leg movements in young healthy subjects. It was hypothesized that with changes in walking velocity there is a change in frequency and phase coupling between the arms and the legs. In addition, it was hypothesized that the preferred frequencies of the different coordination patterns can be predicted on the basis of the resonant frequencies of arms and legs with a simple pendulum model. The kinematics of arms and legs during treadmill walking in seven healthy subjects were recorded with accelerometers in the sagittal plane at a wide range of different velocities (i.e., 0.3–1.3 m/s). Power spectral analyses revealed a statistically significant change in the frequency relation between arms and legs, i.e., within the velocity range 0.3–0.7 m/s arm movement frequencies were dominantly synchronized with the step frequency, whereas from 0.8 m/s onwards arm frequencies were locked onto stride frequency. Significant effects of walking speed on mean relative phase between leg and arm movements were found. All limb pairs showed a significantly more stable coordination pattern from 0.8 to 1.0 m/s onwards. Results from the pendulum modelling demonstrated that for most subjects at low-velocity preferred movement frequencies of the arms are predicted by the resonant frequencies of individual arms (about 0.98 Hz), whereas at higher velocities these are predicted on the basis of the resonant frequencies of the individual legs (about 0.85 Hz). The results support the above-mentioned hypotheses, and suggest that different patterns of coordination, as shown by changes in frequency coupling and phase relations, can exist within the human walking mode.

Effects of age on distally and proximally generated drawing movements: a kinematic analysis of school children and adults

The effects of age on basic fine motor functions were assessed using a kinematic analysis of simple repetitive drawing movements in a sample of 53 right‐handed children aged 7 to 14 years 11 months and 16 adults aged 27 to 54 years with no detectable abnormality with neurological examination. Lines, circles, and half‐circles were drawn at a self‐chosen and maximum velocity with a pressure‐sensitive pen on a computer graphics tablet. Patterns generated by finger, wrist, and arm movements, and those generated by combined finger‐wrist movements with and without a change in the drawing direction were analysed. The frequencies of all movement patterns increased until adulthood: 0.1 Hz per year for half‐circles, 0.15 to 0.2 Hz per year for circles and lines generated by arm and wrist movements. The greatest increase (0.35 Hz per year) was observed for lines produced by finger movements. Differences in movement frequencies between finger versus wrist or arm movements when drawing lines decreased from about 3 Hz in 7– to 8‐year‐olds to 0.5 to 1 Hz in adolescents. In adults the difference between maximum finger, wrist, and arm movement frequencies decreased to almost zero. In contrast, the differences in movement patterns with and without change in direction remained stable until adulthood. Based on these results it is hypothesized that the differential effects of finger and more proximally generated movements on age reflect maturation of distinct neuronal sites of the cortico‐striatal‐cerebellar circuit rather than acquisition of motor skills or myelinization of corticospinal pathways.

Upper trapezius muscle activity patterns during repetitive manual material handling and work with a computer mouse.

Firstly, upper trapezius EMG activity patterns were recorded on the dominant side of 6 industrial production workers and on the side operating a computer mouse of 14 computer-aided design (CAD) operators to study differences in acute muscular response related to the repetitiveness of the exposure. The work tasks were performed with median arm movement frequencies ranging from 5 min −1 to 13 min −1 and were characterized by work cycle times ranging from less than 30 sec to several days. However, the static and median EMG levels and EMG gap frequencies were similar for all work tasks indicating that shoulder muscle loads may be unaffected by large variations in arm movement frequencies and work cycle times. An exposure variation analyses (EVA) showed that the EMG activity patterns recorded during production work were more repetitive than during CAD work, whereas CAD work was associated with more static muscle activity patterns, both may be associated with a risk of developing musculoskeletal symptoms. Secondly, upper trapezius EMG activity patterns recorded on the mouse side of the CAD operators were compared with those recorded on the non-mouse side to study differences in muscular responses potentially related to the risk of developing shoulder symptoms which were more prevalent on the mouse side. The number of EMG gaps on the mouse side were significantly lower than the values for the upper trapezius on the non-mouse side indicating that more continous activity was present in the upper trapezius muscle on the mouse side and EVA analyses showed a more repetitive muscle activity pattern on the mouse side. These findings may be of importance to explain differences in the prevalence of shoulder symptoms.

Something Sinistral Going On? Asymmetry in Arm Movement Frequency

In a test of the hypothesis that the dominant arm would be more active than the nondominant arm, 70 young adults (including 34 left-handers) wore instrumented motion recorders on both wrists for 48 hours. Participants' left arms made approximately 80 more movements per hour than did their right arms, which was unexpected. This mean difference reflected a generalised leftward shift in the distribution of the frequency of arm movements. Two-thirds of the individuals in the sample were characterised by a sinistral bias in arm movement frequencies. Degree of sinistral bias in arm movement frequency was unrelated to hand preference as measured by the Waterloo Inventory. Implications of this new asymmetry are discussed.

Cardiac strain among women workers in an industrial laundry.

Occupational heat exposure standards define permissible thermal conditions on the basis of metabolic heat production. However, even when energy expenditure is low, upright posture and repetitive upper limb motion may influence thermoregulatory behaviour through increased cardiovascular stress. The present study was undertaken to examine the relationship between work activity, thermal exposure and cardiac strain among women laundry workers engaged in sedentary, repetitive work activity. Ambient temperatures, work activity and heart rate were recorded during complete work shifts for 11 women over three days in summer and three days in winter. Workstation temperatures were significantly higher in summer. Analysis of continuous recordings of heart rate with respect to work activity showed (i) parallel increases in pulse rate and dominant arm movement frequency; (ii) different patterns of heart rate fluctuations for the two work cycles, with peaks during particular sub-tasks and when arms were in elevated positions. Recommended limits for cardiac strain indices were surpassed in both seasons, although in summer they were exceeded significantly more frequently. The part of cardiac effort attributable to thermoregulatory adjustments was also higher in summer while the fraction reflecting metabolic needs did not change with the season. These findings demonstrate high levels of cardiac strain in this work situation and raise the question of redefining heat exposure standards to include the prevention of excessive cardiac strain resulting from cumulative effects of heat load and ergonomic stressors.

Adaptation to visual displacement with active and passive limb movements: effect of movement frequency and predictability of movement.

Three experiments were performed to evaluate the influence of active and passive limb movements on adaptation to visual displacement. Over a wide frequency range (0·5-1·25 Hz) with constant amplitude, 30°, significant adaptation was achieved with active and passive movements. When arm movement frequency was constant at 1·0 Hz but amplitude of movement was varied, less adaptation was achieved for both active and passive movements than when amplitude was held constant. Even at a frequency above that of most naturally occurring limb movements, 1·67 Hz, and with variable amplitude motion, significant adaptation was achieved with active and passive limb movements. These findings emphasize the importance of visual-proprioceptive discordances for adaptation to visual displacement when only sight of the hand is permitted. Significant differences did not appear between the active and passive movement conditions in any of the experiments.