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PubMed1995

A behavioral approach to the treatment of urinary incontinence in a disabled population.

Although the literature has indicated that incontinence can be successfully treated with nonsurgical methods in the able-bodied population, there has been little research performed in the disabled population. Fifty-four patients with various disabilities were treated with pelvic muscle exercises, using biofeedback in conjunction with adjustments in their bowel program, caffeine intake, fluid intake, toileting schedules, transfer training, and medications. The average number of incontinent episodes before intervention was 3.6 per day, which was reduced to 0.8 per day after interventions (p < .001). The characteristics associated with treatment success and failure were evaluated and are discussed in this article, In addition, the change in amplitude and duration of the pelvic muscle surface electromyograph were analyzed. A statistical trend (p = .07) was discovered between an increase in amplitude and a positive outcome. There was a statistical association between increased pelvic floor contraction duration and a good or excellent outcome (p < .05). In conclusion, a behavioral approach to treatment of urinary incontinence is efficacious in the disabled population who can volitionally void and can voluntarily contract their pelvic muscles.

Adult↗
PubMed1995

Physiologic responses of cardiac patients to supine, recumbent, and upright cycle ergometry.

Physiological responses were compared in nine stable male cardiac patients (mean +/- standard error (SE): age, 68.3 +/- 8.1 years; height, 172.7 +/- 3.9cm; weight, 72.8 +/- 14.5kg) during stationary cycling in the supine, recumbent, and upright positions. A discontinuous exercise protocol was performed in which each stage included 3 minutes of exercise and 1 minute of recovery. Each subject's workload started at 150kgm.min-1 and increased by 150kgm.min-1 per stage until volitional fatigue. Testing sessions were randomized and performed 1 week apart. Subjects continued their normal medication regimen. All subjects were participants in a community-based cardiac rehabilitation program. Dependent variables were assessed at two different intensities; submaximal (300kgm.min +/- 1) and maximal. A two-way repeated measures ANOVA found no significant differences in systolic blood pressure (SBP), diastolic blood pressure (DBP), minute ventilation (VE), respiratory exchange ratio (R), rate pressure product (RPP), and rating of perceived exertion (RPE) at submaximal (300kgm.min +/- 1) and maximal exercise efforts. Heart rate (HR) was significantly lower (p < or = .05) in the supine position compared with either the upright or recumbent positions during the submaximal workload. In addition, oxygen uptake (VO2) was significantly lower in the supine position at the submaximal workload (p < or = .05) compared with both upright and recumbent. No difference in HR or VO2 was observed at maximal exercise. Regressions of HR on VO2 showed similar slopes and intercepts for supine, recumbent, and upright ergometry.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1996

Implanted Functional Neuromuscular Stimulation systems for individuals with cervical spinal cord injuries: clinical case reports.

OBJECTIVE: To determine the feasibility of providing the ability to stand and to facilitate the performance of standing transfers to individuals with cervical-level spinal cord injuries via functional neuromuscular stimulation (FNS). The applicability of implantable technology to this population was investigated, and the characteristics of the potential system users were explored. The effects of FNS on the effort and assistance required to stand and complete standing transfers were examined. SETTING: Institutional rehabilitation practice. DESIGN: Nonrandomized controlled trial. PATIENTS: Twenty-four individuals with low cervical spinal cord injuries were evaluated for inclusion in a program of lower extremity FNS, four of whom received the intervention. INTERVENTION: Chronically indwelling percutaneous intramuscular electrodes were used to exercise the hip, knee, and trunk extensors and develop activation patterns to produce standing function. These temporary systems were then replaced with silicone-enclosed helical wire electrodes suitable for eventual use with an eight-channel implantable receiver/stimulator. MAIN OUTCOME MEASURES: Full sensory and motor evaluations were performed and physical contraindications to stimulation were catalogued. For active subjects, American Spinal Injury Association Total Motor Scores with and without FNS were recorded, along with quadriceps strength and ability to complete exercise, standing, controlled sitting, and standing transfer maneuvers. Performances of implanted electrodes were determined by the stability of recruitment properties, impedances or surface potentials, and serial radiographs. RESULTS: Motor scores increased an average of nine points with stimulation over baseline volitional values. With FNS, all four volunteers were able to exercise, stand, and sit independently or with minimal assistance. Although they required varying degrees of assistance with the pivot phase of the transfer maneuver, all were able to raise and lower their body weight independently with stimulation and to use the system to facilitate standing transfers. One participant received the implantable receiver/stimulator, which remains operational at follow-up more than 3 years later. CONCLUSION: FNS can provide the ability to exercise, stand, and transfer to individuals with tetraplegia, even in the presence of medical complications and upper extremity impairment. FNS facilitates standing transfers by eliminating the heavy lifting usually required by a caregiver, thus decreasing the effort and assistance necessary to gain access to places impossible to approach with conventional sliding transfers.

Adult↗
PubMed1996

Aerobic walking in slowly progressive neuromuscular disease: effect of a 12-week program.

OBJECTIVE: Poor cardiorespiratory endurance is a common finding in neuromuscular disease (NMD), and the capacity of such patients to respond to aerobic training is unclear. This study was conducted to determine if a 12-week walking program results in increased aerobic capacity in slowly progressive NMD subjects, whether such a program is safely tolerated, and whether such patients can adhere to a self-monitored, home-based training program. DESIGN: Before-after trial. SETTING: Subjects' homes. PATIENTS: A cohort of 8 slowly progressive NMD subjects (4 men, 4 women) followed in the neuromuscular disease clinic participated (age, 36.6 +/- 8.0 yrs; ht, 170 +/- 11 cm; wt, 74.3 +/- 19.0 kg) (Mean +/- SD). INTERVENTION: Subjects walked 15 to 30 min 3 to 4 days a week at 50% to 60% of their heart rate reserve. MAIN OUTCOME MEASURES: Resting, submaximal, and peak heart rates, systolic and diastolic blood pressures, oxygen uptake, and peak power output. RESULTS: Graded exercise testing to volitional fatigue using a semirecumbent cycle ergometer before and after the training program found significant decreases in submaximal heart rate by 7 +/- 3 beats/min (Mean +/- SEM) (95% CI = -23 to 9) (p = .046) and submaximal systolic blood pressure by 11 +/- 4 mmHg (95% CI = -31 to 9) (p = .019), and nonsignificant increases in peak power output and VO2. CONCLUSIONS: These results suggest that moderate-intensity aerobic exercise training is well tolerated and may provide modest improvement in aerobic capacity in slowly progressive NMD subjects.

Adult↗
PubMed1997

Isometric torso rotation strength: effect of training frequency on its development.

OBJECTIVE: To examine training frequency's effect on torso rotation muscle strength. DESIGN: The study followed a pretest-posttest randomized-group design. SETTING: University laboratory. PATIENTS: Subjects, 33 men (age 30 +/- 11yr) and 25 women (age 28 +/- 10yr) with no history of low back pain, volunteered to participate in the study and were tested for isometric (IM) torso rotation strength before (T1) and after (T2) 12 weeks of training. Measurements of maximal voluntary IM torso rotation torque (N.m) were made through a 108 degrees range of motion (54 degrees, 36 degrees, 18 degrees, 0 degree, -18 degrees, -36 degrees, -54 degrees). Subjects were stratified by peak torque at T1, and randomized to a nonexercising control group (C, n = 10), or groups that trained once a week (1x/wk, n = 16), twice a week (2x/wk, n = 17), or three times a week (3x/wk, n = 15); and all groups were similar in strength. INTERVENTIONS: Training consisted of 8 to 12 repetitions of full range dynamic variable resistance exercise to volitional fatigue, for both left and right rotation. MAIN OUTCOME: To determine the best training frequency for the development of torso rotation strength. RESULTS: Relative improvements (average increase in strength gained at each angle) for the training groups were 4.9%, 16.3%, and 11.9% for the 1, 2, and 3x/wk groups, respectively. The 1x/wk group did not increase in IM torso rotation strength compared to the control group at any angle. Both the 2 and 3x/ wk groups increased their IM torso rotation strength compared to the control group at all but one angle. There were no significant differences in IM torso rotation strength between the groups that trained 2 or 3x/wk. During the training period, the 2 and 3x/wk groups increased their dynamic training load significantly more than the 1x/wk group. CONCLUSIONS: Posttraining dynamic strength was not different between training frequencies of 2 and 3x/wk. Therefore, training the rotary torso muscles 2x/wk is recommended.

Adult↗
PubMed2002

Mindsets in social anxiety: a new look at selective information processing.

According to the Rubicon Model of Action Phases (in: J. Gollwitzer, 1996), Motivation, volition, and action, Enzyclopedia of psychology, series "motivation and emotion", Vol. 4, Hogrefe, Göttingen, 1996, pp. 531-582), different stages in goal pursuit are accompanied by different mindsets that enhance processing of mindset-congruous information. Before people engage in action, they usually deliberate possible goals for a given situation (deliberative mindset). Once a goal is chosen, they plan how to achieve this particular goal (implemental mindset). The present experiments tested the hypothesis that people with social anxiety show a reversal of mindsets when approaching social situations. In Experiment 1, 20 students were asked to either deliberate goals for a hypothetical social conflict (deliberation), or to think about steps to solve the conflict (implementation). An unexpected recognition test demonstrated different recognition memory for deliberation-related versus implementation-related information in the two groups, consistent with the hypothesis of different mindsets. In Experiment 2, 48 students who were either high or low in social anxiety were randomly assigned to either the deliberation or the implementation condition. Participants high in social anxiety showed a pattern in the recognition test that was consistent with a reversal of mindsets. When asked to plan social situations, they showed an inappropriate deliberative mindset. In contrast, they lacked a deliberative mindset when deliberating goals for the social situation. The result indicate that socially anxious people engage in information processing that interferes with successful goal attainment when approaching social situations.

Adult↗
PubMed2000

The imbalanced brain: from normal behavior to schizophrenia.

An outstanding problem in psychiatry concerns how to link discoveries about the pharmacological, neurophysiological, and neuroanatomical substrates of mental disorders to the abnormal behaviors that they control. A related problem concerns how to understand abnormal behaviors on a continuum with normal behaviors. During the past few decades, neural models have been developed of how normal cognitive and emotional processes learn from the environment, focus attention and act upon motivationally important events, and cope with unexpected events. When arousal or volitional signals in these models are suitably altered, they give rise to symptoms that strikingly resemble negative and positive symptoms of schizophrenia, including flat affect, impoverishment of will, attentional problems, loss of a theory of mind, thought derailment, hallucinations, and delusions. This article models how emotional centers of the brain, such as the amygdala, interact with sensory and prefrontal cortices (notably ventral, or orbital, prefrontal cortex) to generate affective states, attend to motivationally salient sensory events, and elicit motivated behaviors. Closing this feedback loop between cognitive and emotional centers is predicted to generate a cognitive-emotional resonance that can support conscious awareness. When such emotional centers become depressed, negative symptoms of schizophrenia emerge in the model. Such emotional centers are modeled as opponent affective processes, such as fear and relief, whose response amplitude and sensitivity are calibrated by an arousal level and chemical transmitters that slowly inactivate, or habituate, in an activity-dependent way. These opponent processes exhibit an Inverted-U, whereby behavior becomes depressed if the arousal level is chosen too large or too small. The negative symptoms are owing to the way in which the depressed opponent process interacts with other circuits throughout the brain.

Affect↗
PubMed2003

Neural circuitry underlying voluntary suppression of sadness.

BACKGROUND: The ability to voluntarily self-regulate negative emotion is essential to a healthy psyche. Indeed, a chronic incapacity to suppress negative emotion might be a key factor in the genesis of depression and anxiety. Regarding the neural underpinnings of emotional self-regulation, a recent functional neuroimaging study carried out by our group has revealed that the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex are involved in voluntary suppression of sexual arousal. As few things are known, still, with respect to the neural substrate underlying volitional self-regulation of basic emotions, here we used functional magnetic resonance imaging to identify the neural circuitry associated with the voluntary suppression of sadness. METHODS: Twenty healthy female subjects were scanned during a Sad condition and a Suppression condition. In the Sad condition, subjects were instructed to react normally to sad film excerpts whereas, in the Suppression condition, they were asked to voluntarily suppress any emotional reaction in response to comparable stimuli. RESULTS: Transient sadness was associated with significant loci of activation in the anterior temporal pole and the midbrain, bilaterally, as well as in the left amygdala, left insula, and right ventrolateral prefrontal cortex (VLPFC) (Brodmann area [BA] 47). Correlational analyses carried out between self-report ratings of sadness and regional blood oxygen level dependent (BOLD) signal changes revealed the existence of positive correlations in the right VLPFC (BA 47), bilaterally, as well as in the left insula and the affective division of the left anterior cingulate gyrus (BA 24/32). In the Suppression condition, significant loci of activation were noted in the right DLPFC (BA 9) and the right orbitofrontal cortex (OFC) (BA 11), and positive correlations were found between the self-report ratings of sadness and BOLD signal changes in the right OFC (BA 11) and right DLPFC (BA 9). CONCLUSIONS: These results confirm the key role played by the DLPFC in emotional self-regulation. They also indicate that the right DLPFC and right OFC are components of a neural circuit implicated in voluntary suppression of sadness.

Adult↗
PubMed2000

Electroconvulsive seizures modulate levels of thyrotropin releasing hormone and related peptides in rat hypothalamus, cingulate and lateral cerebellum.

We have studied the neuroanatomic extent of electroconvulsive (ECS)-responsive prepro-TRH and TRH-related gene expression and its possible interaction with forced swimming. Young adult male Wistar rats were treated in a 2x2 Latin square protocol of swimming, no swimming, three daily ECS or sham ECS. Sixteen different brain regions were dissected and immunoreactivity measured for TRH (pGlu-His-Pro-NH(2)); TRH-Gly, a TRH precursor; Ps4, a prepro-TRH-derived TRH-enhancing decapeptide, and EEP (pGlu-Glu-Pro-NH(2)). ECS, in addition to elevating TRH-immunoreactivity (TRH-IR), TRH-Gly-IR, Ps4-IR and EEP-IR levels in the limbic regions, as we have previously reported, also significantly increased Ps4-IR levels in hypothalamus, posterior cingulate and lateral cerebellum, and increased TRH-Gly-IR levels in hypothalamus. Interestingly, the combination of ECS and swimming significantly reduced the levels of TRH-Gly-IR in the anterior cingulate compared to the sham ECS-no swim group. The combined use of high-pressure liquid chromatography and the EEP radioimmunoassay (RIA) revealed that pGlu-Tyr-Pro-NH(2) and/or pGlu-Phe-Pro-NH(2) occur in amygdala, anterior cingulate, frontal cortex, entorhinal cortex, lateral cerebellum and striatum and make a substantial contribution to the EEP-IR and TRH-IR. We conclude that ECS can alter the expression and secretion of TRH-related peptides in the hypothalamus, cingulate and lateral cerebellum. Such effects have not previously been reported in these limbic and extra-limbic regions which are increasingly implicated in the autonomic, behavioral and volitional changes which accompany severe depression and its treatment.

Animals↗
PubMed2006

Intermittent reversal of complete ptosis associated with sphenoid wing meningiomas.

CASE REPORT: Ptosis secondary to dense oculomotor pareses generally improves over several months, but intermittent elevation of the eyelid has not been reported. The authors describe two patients who demonstrated intermittent involuntary monocular eyelid elevation in an eye with complete ptosis caused by partial resection of sphenoid wing meningioma. Both patients had complete ophthalmoplegia and decreased corneal sensation. The involved eye was ipsilateral to a meningioma that had been debulked 11 to 12 months previously. Although the lids were devoid of volitional movement, each patient could elevate the lid for 10 to 20 seconds by either tickling the eyelashes or rubbing the eyelids. The lids occasionally rose spontaneously and there was no clinical evidence of aberrant regeneration or cyclic spasm. COMMENTS: Although the mechanism of action of this involuntary eyelid elevation is unknown, it is possible that some process of aberrant regeneration activated by sensory stimuli is responsible.

Adult↗
PubMed2000

Detection of errors during speech production: a review of speech monitoring models.

In this paper three theories of speech monitoring are evaluated. The perception-based approach proposes that the same mechanism employed in understanding other-produced language, the speech comprehension system, is also used to monitor one's own speech production. A conceptual, an inner, and an auditory loop convey information to a central, conscious monitor which scrutinizes the adequacy of the ongoing speech flow. In this model, only the end-products in the speech production sequences, the preverbal (propositional) message, the phonetic plan, and the auditory results, are verified. The production-based account assumes multiple local, autonomous monitoring devices, which can look inside formulation components. Moreover, these devices might be tuned to various signals from the actual speech motor execution, e.g. efferent, tactile, and proprioceptive feedback. Finally, node structure theory views error detection as a natural outflow of the activation patterns in the node system for speech production. Errors result in prolonged activation of uncommitted nodes, which in turn may incite error awareness. The approaches differ on the points of consciousness, volition and control, the number of monitoring channels, and their speed, flexibility, and capacity, and whether they can account for concurrent language comprehension disorders. From the empirical evidence presently available, it is argued for a central perception-based monitor, potentially augmented with a few automatic, production-based error detection devices.

Humans↗
PubMedDate not supplied

The predelusional state: a conceptual history.

The predelusional state (PDS) is defined as the set of psychopathologic events preceding the crystallization of delusions, and includes strange cognitions, moods, conations, and motor acts that may be fleeting and defy description. This review exclusively deals with the historic aspects of PDS. It is noted that during PDS the patient is expected to report experiences for which, on account of their novelty, he may not even have a name. Thus, it is quite likely that according to culture and personal codes and to the conceptual brief of the interviewer, similar experiences might be reported as depersonalization, bodily sensations, dysphoria, changes in perception of reality or time, dissolution of "ego boundaries," etc. It is therefore not surprising that since the 19th century, PDS has been considered a disorder of cognition, emotions, volition, and consciousness.

Consciousness Disorders↗
PubMed1979

Capacity for holding sustained attention following commissurotomy.

To assess the relative capacities of the two cerebral hemispheres to sustain prolonged mental concentration, the performance of commissurotomized patients and normal controls was tested on monotonous sorting and signal detection tasks. The two series of tasks all required the maintenance of focused attention but differed in the amount of motor activity involved. Results showed that attentional capacity was different for active than for passive tasks in the patient group. During the active sorting tasks, commissurotomy patients were able to sustain continuous attention for periods of up to an hour while in the passive signal detection tasks, a decline in general levels of arousal was evident within ten to twenty minutes. The maintenance of generalized attention with minimal proprioceptive and external stimulation was thus found to be markedly weakened following commissurotomy. Neither hemisphere was consistently inferior to the other in sustaining mental concentration. The unique ability of commissurotomy patients to efficiently carry out mutually conflicting volitional decisions while sorting with the hands simultaneously points up the role of the intact commissures in unifying attentional components of cognitive processing.

Adult↗
PubMed1982

The effects of deep-reaching lesions in the cortical face area on phonation. A combined case report and experimental monkey study.

The present study compares the phonatory ability of a patient with a deep-reaching left-sided lesion in the region of the cortical face area with that of two squirrel monkeys in which the patient's lesion has been reduplicated bilaterally. The lesion involved Broca's area, the inferior pre- and postcentral cortex, rolandic operculum, inferior parietal cortex insula, claustrum, parts of the putamen and white matter underlying the inferior frontoparietal and insular cortex. While the squirrel monkey did not show any phonatory deficits, the patient became aphonic for more than 10 weeks following the insult. After that period, phonation recovered steadily to a slightly breathy but monotonous voice with a somewhat reduced singing capacity. During the aphonic period, there was a bilateral complete paresis of the vocal folds. Both, patient and monkey, showed a paresis of the lower facial and tongue muscles which was accompanied by dysarthria and buccolingual apraxia in the patient and feeding difficulties in the monkey. The discrepancy between human aphonia and intact monkey phonation, on the one hand, and intact phonation and defective orofacial behaviour in the monkey, on the other, is explained by the anatomical fact that there is a direct cortical projection to the nucleus ambiguus in man but not in monkey, whereas the facial and hypoglossal nuclei receive direct cortical projections in man and monkey. The lack of direct cortical control of the laryngeal motoneurones in the monkey is paralleled by a lack of volitional control of fine vocal fold movements.

Animals↗
PubMed1982

The development of facedness.

Thirty-two children of both sexes, ranging in age from 6 to 13 years, were photographed while posing or imitating happiness, sadness or surprise. Full-face photographs which were considered by independent judges to express the intended emotions were submitted to a split-face recombination procedure that created two composites from each face, one from the left side and the other from the right. Independent observers found the left composites to be more expressive than the right in the older group (age 12-13), but not in the younger groups, who evinced no left-right asymmetries. This finding applied similarly to the three emotions, and did not depend on an age-related change in the capacity for emotional expression. Further, left-right asymmetries in facial expression, where present, did not correlate with difference in size between the two halves of the face, and were found for both the upper and lower parts of the face. It is concluded that the advantage of the left hemiface for emotional expression, which is typical of adults, is the result of growth and development. While this facial asymmetry is likely to depend on an hemispheric asymmetry favoring the right side of the brain for the volitional control of the facial musculature, the neural mechanisms of the phenomenon of facedness are still largely obscure.

Age Factors↗
PubMed1996

Supplementary motor area in spatial coordination of bilateral movements: a new aspect to 'the SMA debate'?

To test whether the supplementary motor area's (SMA) role is confined to determining the 'temporal' but not the 'spatial' properties of a movement (H.H. Kornhuber et al., in: W.A. Hershberger (Ed.), Volitional Action, Elsevier, Amsterdam, 1989, pp. 107-168), movement-related scalp-recorded negative DC potential shifts were recorded in bilateral movements requiring complex spatial coordination. In such bilateral continuous rotation movements, the effect of the rotation sense (symmetrical vs. antisymmetrical), i.e. the direction in which an arm or a finger rotated in relation to the other, heavily affected DC shifts over the frontocentral midline. Antisymmetrical rotation of upper limb segments was associated with higher negative DC shifts than symmetrical rotation was. This was true for rotations in the sagittal plane, irrespective of whether the rotation involved predominantly proximal muscles (by a rotation predominantly in the shoulder) or only distal muscles (by a rotation in the metacarpo-phalangeal joint of the index finger). If these negative cortical DC-shifts over the frontocentral midline relate to activity of mesial frontocentral structures including the SMA, then the present results suggest that there is a role for these cerebral areas in spatial coordination of bilateral movements. Surprisingly, this was not the case for similar finger movements performed in the frontal plane. The results of the present study and particularly the considering of some fundamentals of theoretical physics and of Popper's philosophy of science, made us revise our assumption motivating the present study, that time and space would represent two orthogonal factors of a movement and that the contributions of a particular cerebral motor area (such as the SMA) to 'spatial parameters' versus 'temporal parameters' of a movement can thus be teased apart.

Adult↗
PubMed1999

The cortical topography of human anorectal musculature.

BACKGROUND & AIMS: The muscles of the anorectum are important in the volitional control of continence, yet virtually no information exists on their cortical representation in humans. METHODS: Topographic cortical mapping of both cerebral hemispheres was performed in 9 healthy subjects by applying suprathreshold transcranial magnetic stimulation to individual points on a scalp grid centered over the vertex and then recording the electromyographic responses from the external anal sphincter, rectum, and tibialis anterior muscles. RESULTS: Cortically evoked anal and rectal response latencies were similar (20.2 +/- 1.7 and 19.8 +/- 1.5 milliseconds, respectively) and were shorter than those from the anterior tibialis muscle (right, 29.7 +/- 2.3 milliseconds; left, 29.9 +/- 1.8 milliseconds; P < 0.0005). Cortical mapping showed that the anal responses were bilaterally represented on the superior motor cortex (Brodmann area 4) of both cerebral hemispheres; a similar topography was found for the rectal responses. By comparison, the tibialis responses showed predominantly contralateral medial motor cortex representation. Subtle but consistent differences in the degree of bilateral hemispheric representation were also apparent both between and within individuals for the anal responses and to a lesser extent for the rectal responses. CONCLUSIONS: The anorectal musculature has bilateral motor cortex representation with similar topography, but there is intersubject variation in the degree of symmetry.

Adult↗
PubMed2002

Fall arrest strategy affects peak hand impact force in a forward fall.

We measured the peak hand impact force involved in bimanually arresting a forward fall to the ground from a 1-m shoulder height in five healthy young males. The effects of three different subject instruction sets: "arrest the fall naturally"; "keep the head as far from the ground as possible"; and "minimize the peak hand forces" were studied by measuring body segment kinematics, ground reaction forces, and upper-extremity myoelectric activity. The hypotheses were tested that the (a) arrest strategy did not influence peak impact force, (b) arm configuration, impact velocity and upper-extremity electromyography (EMG) levels correlate to the peak impact force (c) and impacting the ground with one hand leading the other does not increase the impact force over that obtained with simultaneous hand use. The results show that these subjects were able to volitionally decrease the peak impact force at the wrist by an average of 27% compared with a "natural landing" (p=0.014) and 40% compared with a "stiff-arm landing" (p<0.0005). The magnitude of the peak unilateral wrist force varied from 0.65 to 1.7 body weight for these moderate falls onto a padded surface. Peak force correlated with the elbow angle at impact, wrist velocity at impact and with pre-EMG triceps activity. The force was not significantly higher for non-simultaneous hand impacts. We conclude that fall arrest strategy can substantially alter the peak impact forces applied to the distal forearm during a fall arrest. Therefore, the fall arrest strategy likely influences wrist injury risk independent of bone strength.

Accidental Falls↗