Predictive Contribution of the Superficial Neck Muscles to Short-Latency Rate of Force Development of the Head and Neck.

PURPOSE: To evaluate the contribution of splenius capitis, sternocleidomastoid, and upper fibers of trapezius activation to the gains in rate of force development (RFD) of the head and neck during maximum voluntary ballistic contractions. METHODS: RFD gain was facilitated by a single-session intervention for maximum voluntary ballistic contractions in the anterior direction, oriented at 45° to the midsagittal plane, which require active restraint of axial rotation. Muscle activation for the agonist (sternocleidomastoid) and 2 antagonists (splenius capitis and upper fibers of trapezius) was evaluated. The study sample included 12 physically active men (mean age, 22.6 y). RFD (N·m·s-1; 0-100 ms) and integrated muscle activity (50 ms before and 100 ms after force onset) were measured at 10 minutes, 20 minutes, and 2 days postintervention, relative to baseline. Muscle activation predictive of RFD gains was evaluated by linear regression analysis. RFD reproducibility was evaluated using the coefficient of variation of the typical error. RESULTS: The intervention yielded a 1.95- to 2.39-fold RFD gain (P ≤ .05), with greater RFD gain for participants with a lower peak moment of force (<10.9 N·m) than those with a higher peak moment (≥10.9 N·m) at baseline (P ≤ .002). For the low group, 65% to 74% of the RFD gain was predicted by ipsilateral sternocleidomastoid activation, with ipsilateral splenius capitis activation predicting 77% to 92% of RFD gain for the high group. Absolute peak and impulse of static force were greater for the high than for the low group (P ≤ .04). RFD reproducibility was high (coefficient of variation of the typical error ≤ 14.4%). CONCLUSIONS: The agonist- and antagonist-focused synergies might reflect different functional priorities, higher RFD gain compared with higher head-neck force.

Prevalence of musculoskeletal pain among gynecologic surgeons performing laparoscopic procedures: A systematic review and meta-analysis.

OBJECTIVE: Musculoskeletal discomfort is associated with repetitive movements and constrained body positions. The current meta-analysis was performed to determine the global prevalence of musculoskeletal symptoms among gynecologic surgeons who perform laparoscopy. METHODS: Sources included Embase, MEDLINE, PubMed, CINAHL, Web of Science Core Collection, Cochrane Central Register of Controlled Clinical Trials, and Google Scholar. Articles published between 1980 and 2022 were considered. Studies that assessed self-reported musculoskeletal symptoms were included. Relevant data were extracted and tabulated. RESULTS: Twelve studies met the inclusion criteria. In a pooled sample of 1619 surgeons, the estimated prevalence of musculoskeletal symptoms was 82% (95% confidence interval [CI], 70%-89%; I2 , 92%). Female sex was a risk factor, as identified by a pooled odds ratio of 4.64 (95% CI, 2.63-8.19; I2 , 0%) compared with male surgeons. Among surgeons who reported musculoskeletal symptoms, 30% (95% CI, 14%-52%; I2 , 95%) sought treatment and 3% (95% CI, 2%-6%; I2 , 0%) required work hour modifications. CONCLUSION: The current meta-analysis provides preliminary evidence of a high prevalence of musculoskeletal symptoms among gynecologic laparoscopic surgeons. Future research is needed to explore the underlying risk factors and interventional strategies to mitigate this risk.

Effect of early supervised physiotherapy on recovery from acute ankle sprain: randomised controlled trial.

OBJECTIVE:  To assess the efficacy of a programme of supervised physiotherapy on the recovery of simple grade 1 and 2 ankle sprains. DESIGN:  A randomised controlled trial of 503 participants followed for six months. SETTING:  Participants were recruited from two tertiary acute care settings in Kingston, ON, Canada. PARTICIPANTS:  The broad inclusion criteria were patients aged ≥16 presenting for acute medical assessment and treatment of a simple grade 1 or 2 ankle sprain. Exclusions were patients with multiple injuries, other conditions limiting mobility, and ankle injuries that required immobilisation and those unable to accommodate the time intensive study protocol. INTERVENTION:  Participants received either usual care, consisting of written instructions regarding protection, rest, cryotherapy, compression, elevation, and graduated weight bearing activities, or usual care enhanced with a supervised programme of physiotherapy. MAIN OUTCOME MEASURES:  The primary outcome of efficacy was the proportion of participants reporting excellent recovery assessed with the foot and ankle outcome score (FAOS). Excellent recovery was defined as a score ≥450/500 at three months. A difference of at least 15% increase in the absolute proportion of participants with excellent recovery was deemed clinically important. Secondary analyses included the assessment of excellent recovery at one and six months; change from baseline using continuous scores at one, three, and six months; and clinical and biomechanical measures of ankle function, assessed at one, three, and six months. RESULTS:  The absolute proportion of patients achieving excellent recovery at three months was not significantly different between the physiotherapy (98/229, 43%) and usual care (79/214, 37%) arms (absolute difference 6%, 95% confidence interval -3% to 15%). The observed trend towards benefit with physiotherapy did not increase in the per protocol analysis and was in the opposite direction by six months. These trends remained similar and were never statistically or clinically important when the FAOS was analysed as a continuous change score. CONCLUSIONS:  In a general population of patients seeking hospital based acute care for simple ankle sprains, there is no evidence to support a clinically important improvement in outcome with the addition of supervised physiotherapy to usual care, as provided in this protocol.Trial registration ISRCTN 74033088 (www.isrctn.com/ISRCTN74033088).

Effects of head flexion posture on the multidirectional static force capacity of the neck.

BACKGROUND: Neck muscle force protects vertebral alignment and resists potentially injurious loading of osteoligamentous structures during head impacts. As the majority of neck muscles generate moments about all three planes of motion, it is not clear how the force capacity of the neck might be modulated by direction of force application and head posture. The aim of our study was to measure the multidirectional moment-generating capacity of the neck and to evaluate effects of 20° of head flexion, a common head position in contact sports, on the measured capacity. METHODS: We conducted a cross-sectional study, with 25 males, 20-30years old, performing maximum voluntary contractions, with ballistic intent, along eight directions, set at 45° intervals in the horizontal plane of the head. Three-dimensional moments at C3 and T1 were calculated using equations of static equilibrium. The variable of interest was the impulse of force generated from 0-50ms. Effects of direction of force application and head posture, neutral and 20° flexion, were evaluated by two-way analysis of variance and linear regression. FINDINGS: Impulse of force was lower along diagonal planes, at 45° from the mid-sagittal plane, compared to orthogonal planes (P<0.001). Compared to neutral posture, head flexion produced a 55.2% decrease in impulse capacity at C3 and 45.9% at T1. INTERPRETATION: The risk of injury with head impact would intrinsically be higher along diagonal planes and with a 20° head down position due to a lower moment generating capacity of the neck in the first 50ms of force application.

Sensory-motor deficits in children with fetal alcohol spectrum disorder assessed using a robotic virtual reality platform.

BACKGROUND: Fetal alcohol spectrum disorder (FASD) is associated with a large number of cognitive and sensory-motor deficits. In particular, the accurate assessment of sensory-motor deficits in children with FASD is not always simple and relies on clinical assessment tools that may be coarse and subjective. Here we present a new approach: using robotic technology to accurately and objectively assess motor deficits of children with FASD in a center-out reaching task. METHODS: A total of 152 typically developing children and 31 children with FASD, all aged between 5 and 18 were assessed using a robotic exoskeleton device coupled with a virtual reality projection system. Children made reaching movements to 8 peripheral targets in a random order. Reach trajectories were subsequently analyzed to extract 12 parameters that had been previously determined to be good descriptors of a reaching movement, and these parameters were compared for each child with FASD to a normative model derived from the performance of the typically developing population. RESULTS: Compared with typically developing children, the children with FASD were found to be significantly impaired on most of the parameters measured, with the greatest deficits found in initial movement direction error. Also, children with FASD tended to fail more parameters than typically developing children: 95% of typically developing children failed fewer than 3 parameters compared with 69% of children with FASD. These results were particularly pronounced for younger children. CONCLUSIONS: The current study has shown that robotic technology is a sensitive and powerful tool that provides increased specificity regarding the type of motor problems exhibited by children with FASD. The high frequency of motor deficits in children with FASD suggests that interventions aimed at stimulating and/or improving motor development should routinely be considered for this population.

A developmental perspective on congenital muscular torticollis: a critical appraisal of the evidence.

PURPOSE: The aims of this review were to (1) identify and evaluate research evidence regarding the developmental outcomes of infants with congenital muscular torticollis (CMT) and (2) critically appraise and compare the outcomes of interventions targeting neck muscle extensibility and strength with those considering neck muscle function within the broader context of global infant development. SUMMARY: An association between CMT and early developmental delay is supported by levels 3B, 4, and 5 evidence; no evidence was found of longer-term influences of CMT on the development of perceptual, cognitive, and motor skills. The effectiveness of passive manual stretching is supported by levels 2A, 3B, 4, and 5 evidence; no clear evidence was found of the effectiveness of developmentally supportive interventions. CONCLUSION: Controlled studies are needed to clarify the developmental consequences of CMT.

Retest reliability of force-time variables of neck muscles under isometric conditions.

CONTEXT: Proper conditioning of the neck muscles may play a role in reducing the risk of neck injury and, possibly, concussions in contact sports. However, the ability to reliably measure the force-time-based variables that might be relevant for this purpose has not been addressed. OBJECTIVE: To assess the between-days reliability of discrete force-time-based variables of neck muscles during maximal voluntary isometric contractions in 5 directions. DESIGN: Cohort study. SETTING: University research center. PATIENTS OR OTHER PARTICIPANTS: Twenty-six highly physically active men (age  =  21.6 ± 2.1 years, height  =  1.85 ± 0.09 m, mass  =  81.6 ± 9.9 kg, head circumference  =  0.58 ± 0.01 m, neck circumference  =  0.39 ± 0.02 m). INTERVENTION(S): We used a custom-built testing apparatus to measure maximal voluntary isometric contractions of the neck muscles in 5 directions (extension, flexion, protraction, left lateral bending, and right lateral bending) on 2 separate occasions separated by 7 to 8 days. MAIN OUTCOME MEASURE(S): Variables measured were peak force (PF), rate of force development (RFD), and time to 50% of PF (T(50)PF). Reliability indices calculated for each variable comprised the difference in scores between the testing sessions, with corresponding 95% confidence intervals, the coefficient of variation of the typical error of measurement (CV(TE)), and intraclass correlation coefficients (ICC [3,3]). RESULTS: No evidence of systematic bias was detected for the dependent measures across any movement direction; retest differences in measurements were between 1.8% and 2.7%, with corresponding 95% confidence interval ranges of less than 10% and overlapping zero. The CV(TE) was lowest for PF (range, 2.4%-6.3%) across all testing directions, followed by RFD (range, 4.8%-9.0%) and T(50)PF (range, 7.1%-9.3%). The ICC score range for all dependent measures was 0.90 to 0.99. CONCLUSIONS: Discrete variables representative of the force-generating capacity of neck muscles under isometric conditions can be measured with an acceptable degree of reliability. This finding has possible applications for investigating the role of neck muscle strength-training programs in reducing the risk of injuries in sport settings.

Between-day reliability of electromechanical delay of selected neck muscles during performance of maximal isometric efforts.

BACKGROUND: The purpose of this study was to assess the between-day reliability of the electromechanical delay (EMD) of selected neck muscles during the performance of maximal isometric contractions in five different directions. METHODS: Twenty-one physically active males participated in two testing sessions separated by seven to eight days. Using a custom-made fixed frame dynamometer, cervical force and surface electromyography (EMG) were recorded bilaterally from the splenius capitis, upper trapezius and sternocleidomastoid muscles during the performance of efforts in extension, flexion, left and right lateral bending, and protraction. The EMD was extracted using the Teager-Kaiser Energy Operator. Reliability indices calculated for each muscle in each testing direction were: the difference in scores between the two testing sessions and corresponding 95% confidence intervals, the standard error of measurement (SEM) and intra-class correlation coefficients (ICC). RESULTS: EMD values showed no evidence of systematic difference between the two testing sessions across all muscles and testing directions. The SEM for extension, flexion and lateral bending efforts ranged between 2.5 ms to 4.8 ms, indicating a good level of measurement precision. For protraction, SEM values were higher and considered to be imprecise for research and clinical purposes. ICC values for all muscles across all testing directions ranged from 0.23 to 0.79. CONCLUSION: EMD of selected neck muscles can be measured with sufficient precision for the assessment of neck muscle function in an athletic population in the majority of directions tested.

Short-term natural recovery of ankle sprains following discharge from emergency departments.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To examine the natural recovery from grade I and II ankle injuries over a 1-month period. BACKGROUND: There is a high rate of injury recurrence and persistence of symptoms following ankle sprains, suggesting that these injuries may not be adequately managed. However, little is known about the recovery process after discharge from emergency departments. METHODS AND MEASURES: Clinical assessment of ankle swelling, strength, and joint mobility and laboratory assessment of peak torque and joint range of motion (ROM) were performed 4 and 30 days following initial clinical assessment in the emergency department. Analyses for repeated measures determined change over time and differences between injured and noninjured ankles. Self-assessed ankle function was evaluated on day 4 and day 30, and its relationship to clinical and laboratory assessments determined. RESULTS: Forty-six subjects entered the study and complete datasets were obtained from 28. Significant swelling, weakness, and mobility restrictions were evident on initial assessment. Symptoms improved over time and, while clinical variables were normal by day 30, laboratory assessment indicated weakness of plantar flexors and limited active and passive ROM at 1 month. Swelling and reduced passive ROM were associated with overall function and limitations in sports and recreation activities, as well as quality of life 1 month postinjury. CONCLUSION: Clinically assessed strength and ankle dorsiflexion mobility suggested full recovery at 1 month post injury, yet more sensitive measures of ankle impairment and performance detected residual deficits. Persistent impairment and incomplete recovery of self-assessed function suggest the need for management beyond standard emergency department care. Associations between impairment measures and function may provide guidance for treatment intervention.

Kinetic analysis of forwards and backwards stair descent.

The activity of descending stairs increases loading at the joints of the lower extremities as compared to walking, which may cause discomfort and or difficulties in completing the task. This study compared and contrasted the kinematics and kinetics of both forwards and backwards stair descent to those of level walking. We compared the support moments and moment powers of the lower limb joints while descending stairs forwards at a self-selected pace, backwards at a self-selected pace and forwards at the same pace as backwards. Participants were 10 healthy young adults (6 men and 4 women) aged 20-35 years. Sagittal plane kinematics and ground reaction forces were collected and moments of force computed using inverse dynamics. The ratio of stance/swing phase changed from 59:41 for normal level walking to between 65:35 and 70:30 for forward stair descent but backwards descent was 58:42. Stair descent produced larger double-peak support moments with reduced ankle plantar flexor and increased knee extensor moments as compared to level walking (>+/-95th-percentile confidence interval). The hip moments during stair descent were relatively small and highly variable. We observed significantly larger distances between the centres of pressure and the stair edges for backwards stair descent versus forwards stair descent. These results demonstrate that stair descent, even at a slower pace, requires greater power from the knee extensors than level walking but that backwards stair descent significantly reduced the peak knee power during midstance and provided a potentially safer means of descending stairs than forwards stair descent.

Efficacy of continuous passive motion following total knee arthroplasty: a metaanalysis.

OBJECTIVE: The objective of this metaanalysis is to examine the effectiveness of continuous passive motion (CPM) following total knee arthroplasty (TKA). METHODS: This metaanalysis used the methodology proposed by the Cochrane Collaboration. RESULTS: This review of 14 studies (952 patients) found significant improvements in active knee flexion and analgesic use 2 weeks postoperatively with the use of CPM and physiotherapy (PT) compared to PT alone. In addition, length of hospital stay and need for knee manipulations were significantly decreased in the CPM group. Not enough data were available to compare the degree of knee flexion applied or number of hours of application of CPM. However, significant results were not found for other comparisons such as short term CPM application versus longterm CPM application and wide treatment range versus small treatment range for the outcomes of active knee flexion, passive knee flexion and extension, presence of a fixed flexion deformity, use of analgesic, or total knee range of motion. CONCLUSION: CPM combined with PT may offer beneficial results for patients post-TKA. However, the potential benefits will need to be carefully weighed against the inconvenience and expense of CPM. More research is necessary to assess the differences in effectiveness with different characteristics of application such as total duration of treatment and intensity of CPM interventions.

A pattern recognition technique to characterize the differential modulation of co-activating muscles at the performer/environment interface.

The purpose of this research was to develop and test an analytical tool that would recognize and classify the surface electromyographic (EMG) signal of co-activating muscles of the leg into pre-defined patterns of muscle activity: burst, tonic, and tonic-burst. Developed to study the task of landing from a jump in children, the pattern recognition technique (PRT) quantifies the full-wave rectified surface EMG signal over a short-duration sampling window by a single linear regression value. Shifting the sampling window across the data string ultimately defines the signal by a set of regression values that produce the recognizable burst, tonic and tonic-burst patterns on a least-squares surface plot. Statistical comparison of the PRT to the classical combination of threshold detection (+2 S.D. of mean baseline activity) and visual inspection proves the PRT to be more reliable on repeated measures for event detection and classification, with a Kappa statistic of 0.83 compared to 0.54 for threshold detection. Application of the PRT to motor control studies is presented for the regulation of the mechanical response of the leg during impact. Responsiveness of the PRT is tested, issues of accuracy and validity are addressed, and limitations in spatial-temporal resolution are identified.

The Montréal Rehabilitation Performance Profile: a statistical model for assessing stair descent in children with cognitive impairments.

OBJECTIVES: To characterize the responsiveness of the Montréal Rehabilitation Performance Profile (MRPP); to measure the differential effectiveness of a task-specific (TS) and a task-nonspecific (TNS) motor learning format to promote alternating stair descent in children with cognitive impairments; and to evaluate the relevance of the MRPP to evidence-based practice. DESIGN: Randomized comparison of 2 age-matched groups; psychometric testing of measurement tool. SETTING: School for children with developmental and cognitive impairments. PARTICIPANTS: Ambulatory sample of convenience: 18 children, age 5 to 9 years, with moderate to severe cognitive impairment. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The MRPP variables measured at baseline; end of 10-week intervention; and 5 and 10 weeks postintervention. Analysis of variance for repeated measures and part-whole correlation. RESULTS: Global stair descent performance improved for both TS and TNS groups over time (P=.001). However, a specific acquisition and retention of the alternating pattern of descent was associated with the TS format. CONCLUSION: The MRPP was responsive to small differences in stair descent performance that are specific to the format of the motor learning intervention. The MRPP allows clinicians to determine the timing of the intervention needed to maintain or improve stair descent ability.