Maximal Protraction Research Articles

Interrater Reliability of a Novel Goniometric Technique to Measure Scapular Protraction and Retraction.

Scapular protraction and retraction are often essential for occupational performance; however, clinical assessment of these movements is uniquely challenging. To analyze the interrater reliability of a novel goniometric method to measure scapular protraction and retraction. An observational, descriptive design was implemented to evaluate interrater reliability between two experienced occupational therapists who were also certified hand therapists. Academic institution. Convenience sample of graduate students (N = 80). Outcomes and Measures: The hypothesis, developed before study implementation, was that the technique would demonstrate clinically acceptable interrater reliability, defined as a standard error of measurement (SEM) <8°. Goniometric measurements of the scapula at rest, in maximal protraction, and in maximal retraction were independently obtained from each participant by each evaluator. The goniometer was aligned on the scapula using the superior angle as the axis of motion to measure the movement of the acromion relative to the frontal plane. The SEM was calculated in each position using the intraclass correlation coefficient values and the average of the standard deviations from the two raters. The SEM values between the two evaluators for the resting, protracted, and retracted positions were 3.46°, 2.93°, and 2.74°, respectively. The SEM between the two evaluators for each scapular position was <4°, suggesting that the technique may be clinically reliable. However, additional research regarding the reliability and validity of the technique is recommended. What This Article Adds: The findings of this study support the use of goniometry to measure scapular protraction and retraction in relation to occupational performance. The technique provides a way to quantify baseline scapular mobility and track progress.

Kinematic gait characteristics of straight line walk in clinically sound dairy cows.

The aim of this study is to describe the kinematic gait characteristics of straight line walk in clinically sound dairy cows using body mounted Inertial Measurement Units (IMUs) at multiple anatomical locations. The temporal parameters used are speed and non-speed normalized stance duration, bipedal and tripedal support durations, maximal protraction and retraction angles of the distal limbs and vertical displacement curves of the upper body. Gait analysis was performed by letting 17 dairy cows walk in a straight line at their own chosen pace while equipped with IMU sensors on tubera sacrale, left and right tuber coxae (LTC and RTC), back, withers, head, neck and all four lower limbs. Data intervals with stride by stride regularity were selected based on video data. For temporal parameters, the median was calculated and 95% confidence intervals (CI) were estimated based on linear mixed model (LMM) analysis, while for limb and vertical displacement curves, the median and most typical curves were calculated. The temporal parameters and distal limb angles showed consistent results with low variance and LMM analysis showed non-overlapping CI for all temporal parameters. The distal limb angle curves showed a larger and steeper retraction angle range for the distal front limbs compared with the hind limbs. The vertical displacement curves of the sacrum, withers, LTC and RTC showed a consistent sinusoidal pattern while the head, back and collar curves were less consistent and showed more variation between and within cows. This kinematic description might allow to objectively differentiate between normal and lame gait in the future and determine the best anatomical location for sensor attachment for lameness detection purposes.

Effects of sand, asphalt and 3-degree hind toe or heel elevation on horse kinematics.

Although the effects of both the surfaces and plantar angles on equine locomotion have been widely discussed, limited scientific data are available. Our objectives were to determine the effects of two surfaces (asphalt and sand) and of 3-degree hind toe or heel elevation on horse kinematics in an experimental study. Six saddle horses were shod with a reference shoeing (REF), characterized by a fore aluminium (REF F) and hind steel racehorse (REF H) shoeing. Two dimensional kinematic videos compared horse's kinematic parameters when walking and trotting on asphalt and sand. On asphalt, REF was also compared with REF F and a modified REF H with additional 3-degree hind-toe or -heel wedges. On asphalt versus sand, horses had, at the trot, a shorter stride duration and forelimb maximal retraction, and at walk and trot, a greater fetlock, carpus, elbow and tarsus extension, a greater fore and hind limbs maximal protraction and a shorter hind limbs maximal retraction. Increasing the plantar angle decreased the tarsus and hind fetlock extension, in contrast to fore-limb, on asphalt during the stance phase. These findings could be useful to adapt rehabilitation programs related to fore and hind limb pathologies, at slow gaits.

Electromyographic activity of the serratus anterior and pectoralis major during isometric scapular protraction at different resistance intensities in subjects with and without a winged scapula

BackgroundDuring maximal isometric protraction, it is important to determine the optimal resistance intensity in subjects with a winged scapula, for inducing isolated activity of the serratus anterior against the pectoralis major, which is activated as a synergistic muscle. The aim of the present study was to determine electromyographic activities of the serratus anterior and pectoralis major muscles during isometric shoulder protraction at different levels in subjects with and without a winged scapula. MethodsThirty male subjects performed isometric shoulder protraction in a sitting position at different resistance intensity levels (100%, 80%, and 60% of maximal protraction strength). Surface electromyographic data of the serratus anterior and pectoralis major muscles were gathered simultaneously using fixed instrumentation to measure isometric shoulder protraction. FindingsMuscle activity of the serratus anterior in subjects without a winged scapula was significantly greater than that of subjects with a winged scapula across all three conditions, whereas muscle activity of the pectoralis major was lower in subjects without a winged scapula. In addition, winged scapula muscle activity corresponding to maximal protraction was significantly greater than that in the submaximal condition. InterpretationIn a clinical setting, submaximal resistance can be more optimal than maximal effort during isometric shoulder protraction in individuals with a winged scapula.

A Comparison of Protraction-Retraction of the Distal Limb During Treadmill and Water Treadmill Walking in Horses

The amount of protraction-retraction of the limbs during water treadmill (WT) walking has implications for postural and muscular development of horses undertaking this exercise for training and rehabilitation purposes. The objective of this study was to compare protraction-retraction of both forelimbs (FLs) and hind limbs (HLs) during dry treadmill (DT) and WT exercise at the typical walking speed of each as used in practice. Inertial motion sensors attached to the metacarpal/metatarsal bones were used to compare maximal protraction (PROMAX), retraction (RETMAX), and total protraction-retraction range of movement (ROM) across five walking conditions: DT at 1.6 m/s; and WT at 0.8 m/s at four water depths, hoof depth (WTHOOF), fetlock depth (WTFET), hock depth (WTHOCK), and stifle depth (WTSTIFLE). Forelimb ROM was lowest at WTSTIFLE and significantly lower than DT (P < .001). Hind limb ROM was highest at WTSTIFLE and significantly greater than DT (P < .001). Forelimb PROMAX was significantly lower at WTHOCK (P = .001) and WTSTIFLE (P < .001) than DT. Hind limb RETMAX was higher at WTHOCK (P = .001) than on DT and was significantly greater at WTSTIFLE and WTHOCK than WTFET (P < .001 and P = .001, respectively). Walking slowly (0.8 m/s) on a WT reduces FL protraction-retraction ROM and increases HL protraction-retraction ROM when compared with walking at normal speed (1.6 m/s) on a DT. The potential for FL protraction to be decreased and HL retraction to be increased should be taken into account when designing training and rehabilitation programs using this exercise modality.

Examining upper limb kinematics and dysfunction of breast cancer survivors in functional dynamic tasks

BackgroundComorbidities within the breast cancer population can reduce quality of life. Current breast cancer survivor upper limb kinematic strategies unfortunately lack robust connection with performing important activities of daily living. MethodsAccordingly, fifty breast cancer survivors performed 88 dynamic tasks (divided into range of motion-reach, range of motion-rotate, activity of daily living, and work tasks). Humerothoracic and scapulothoracic angles were extracted from motion capture data. Bilateral differences existed for range of motion, and maximal and minimal scapulothoracic and humerothoracic angles. FindingsGenerally, the affected side used less range of motion across task types. Humerothoracic angles on the affected side experienced 6.7° less range of motion in plane of elevation in range of motion-reach (p < 0.01), 2.3° less elevation angle range of motion in range of motion-rotate (p = 0.01), and 7.1° more internal rotation range of motion in range of motion-rotate (p < 0.01). Scapulothoracic angles on the affected side had 2° more anterior/posterior tilt range of motion in work tasks (p = 0.03), 3.4° less maximal protraction in activity of daily living tasks (p = 0.01), and 3.5° less minimum downward rotation in range of motion-rotate (p < 0.01). InterpretationA reduced range of motion on the affected side suggests the breast cancer population had less varied movement strategies, keeping movements in narrower ranges to avoid disability, pain, or subacromial impingement. This investigation produced an unprecedentedly diverse collection of three-dimensional humerothoracic and scapulothoracic kinematics for a breast cancer population. Documentation of physical capability, dysfunction, and adaptive strategies is a crucial step towards developing targeted strategies for enhancing functional recovery in breast cancer survivors.

Effects of horizontal shoulder abduction and adduction on the activity and strength of the scapular protractors

Increased activity of the serratus anterior (SA) muscle combined with decreased activity of the pectoralis major (PM) muscle during scapular protraction exercise is a widely used method for selective strengthening of the former muscle. However, the role played by the PM during maximal scapular protraction remains unclear. The objective of our study was to investigate the effects of horizontal shoulder abduction (decreasing PM activity) and adduction (increasing activity) on the strength and activity of the scapular protractors (the SA and PM) during maximal protraction. Twenty-nine healthy males performed maximal scapular protraction combined with horizontal shoulder abduction or adduction. The strength and activity of the PM and SA decreased significantly (both p < 0.01) during maximal scapular protraction combined with horizontal shoulder abduction, compared with maximal scapular protraction alone, but increased significantly (both p < 0.01) when maximal scapular protraction was combined with horizontal shoulder adduction. We thus conclude that the PM stabilizes the activated SA during maximal scapular protraction, which effectively increases SA activity and scapular protraction strength in the serratus punch posture.

Direction-Specific Impairments in Cervical Range of Motion in Women with Chronic Neck Pain: Influence of Head Posture and Gravitationally Induced Torque.

BackgroundCervical range of motion (ROM) is commonly assessed in clinical practice and research. In a previous study we decomposed active cervical sagittal ROM into contributions from lower and upper levels of the cervical spine and found level- and direction-specific impairments in women with chronic non-specific neck pain. The present study aimed to validate these results and investigate if the specific impairments can be explained by the neutral posture (defining zero flexion/extension) or a movement strategy to avoid large gravitationally induced torques on the cervical spine.MethodsKinematics of the head and thorax was assessed in sitting during maximal sagittal cervical flexion/extension (high torque condition) and maximal protraction (low torque condition) in 120 women with chronic non-specific neck pain and 40 controls. We derived the lower and upper cervical angles, and the head centre of mass (HCM), from a 3-segment kinematic model. Neutral head posture was assessed using a standardized procedure.FindingsPrevious findings of level- and direction-specific impairments in neck pain were confirmed. Neutral head posture was equal between groups and did not explain the direction-specific impairments. The relative magnitude of group difference in HCM migration did not differ between high and low torques conditions, lending no support for our hypothesis that impairments in sagittal ROM are due to torque avoidance behaviour.InterpretationThe direction- and level-specific impairments in cervical sagittal ROM can be generalised to the population of women with non-specific neck pain. Further research is necessary to clarify if torque avoidance behaviour can explain the impairments.

Posture and mobility of the upper body quadrant and pulmonary function in COPD: an exploratory study.

ABSTRACTBackgroundThere is limited evidence regarding interactions between pulmonary (dys)function, posture, and mobility of the upper body quadrant in patients with chronic obstructive pulmonary disease (COPD).ObjectivesThis exploratory study aimed to investigate whether postural alignment and mobility of the upper quadrant are related to changes in pulmonary function and compare such variables between patients with COPD and healthy individuals.MethodFifteen patients with COPD (67.93±9.71yrs) and 15 healthy controls (66.80±7.47yrs) participated. Pulmonary function (FEV1, FVC) was assessed with spirometry. Alignment and mobility of the head, thoracic spine, and shoulder were assessed using digital photographs. Pectoralis minor muscle (PmM) length and thoracic excursion were assessed with a measuring tape. Groups were compared and linear regression analyses were used to assess potential relationships between postural and mobility variables and pulmonary function.ResultsPatients with COPD were more likely to have a forward head position at maximal protraction (28.81±7.30º vs. 35.91±8.56º, p=0.02) and overall mobility of the head (21.81±10.42º vs. 13.40±7.84º, p=0.02) and a smaller range of shoulder flexion (136.71±11.91º vs. 149.08±11.58º, p=0.01) than controls. Patients’ non-dominant PmM length and maximal head protraction were predictors of FEV1 (r2 adjusted=0.34). These variables, together with the upper thoracic spine at maximal flexion and thoracic kyphosis at maximal extension, were predictors of FVC (r2 adjusted=0.68).ConclusionOur findings suggest that impaired pulmonary function is associated with muscle length and mobility adaptations. Further studies are needed to understand the underlying mechanisms and clinical value of these relationships.

Altering Scapular Position Reduces Isometric Shoulder Strength

BackgroundStrength assessment is an integral part of many clinical tests and some outcome measures. However, shoulder strength may not only be influenced by pathology or treatment effect, but also by scapular position. The present study aimed to examine the influence of scapular positioning on shoulder strength.MethodsSixteen normal volunteers (seven males and nine females; mean age 35 years) conducted maximal isometric elevation strength tests in scapular positions of self-selected neutral (SN), maximal protraction (SP), maximal retraction (SR) and posterior tilt (ST), with all of these being assessed in the scapular plane. A prospective, repeated measure, balanced protocol was employed.ResultsResultant strengths were SN = 6.5 kg, SP = 5.0 kg, SR = 5.3 kg and ST = 5.0 kg. Analysis of variance was significant ( p = 0.002) with post-hoc analysis revealing SN as being significantly stronger than SP ( p = 0.002), SR ( p = 0.004) and ST ( p = 0.001). There were no significant differences between SP, SR and ST. Test – retest analysis yielded intraclass correlation coefficients exceeding 0.85.ConclusionsAltering scapula position may affect shoulder strength in asymptomatic individuals. This has implications for the validity and reliability of shoulder tests and outcome measures that are reliant upon shoulder strength, at the same time as supporting the premise that the application of scapula correction exercises should be based upon individual assessment rather than general prescription.

Scapular-Muscle Performance: Two Training Programs in Adolescent Swimmers

Swimming requires well-balanced scapular-muscle performance. An additional strength-training program for the shoulders is pursued by swimmers, but whether these muscle-training programs need to be generic or specific for endurance or strength is unknown. To evaluate isokinetic scapular-muscle performance in a population of adolescent swimmers and to compare the results of training programs designed for strength or muscle endurance. Controlled laboratory study. University human research laboratory. Eighteen adolescent swimmers. Each participant pursued a 12-week scapular-training program designed to improve either muscle strength or muscle endurance. Bilateral peak force, fatigue index, and protraction/retraction strength ratios before and after the scapular-training program. Scapular protraction/retraction ratios were slightly higher than 1 (dominant side = 1.08, nondominant side = 1.25, P = .006). Side-to-side differences in retraction strength were apparent both before and after the training program (P = .03 and P = .05, respectively). After the training program, maximal protraction (P < .05) and retraction (P < .01) strength improved on the nondominant side. Peak force and fatigue index were not different between the training groups. The fatigue indexes for protraction on both sides (P < .05) and retraction on the nondominant side (P = .009) were higher after the training program. We describe the scapular-muscle characteristics of a group of adolescent swimmers. Both muscle-strength and muscle-endurance programs improved absolute muscle strength. Neither of the strength programs had a positive effect on scapular-muscle endurance. Our results may be valuable for coaches and physiotherapists when they are designing exercise programs for swimmers.

Sensation-Targeted Motor Control: Every Spike Counts? Focus on: “Whisker Movements Evoked by Stimulation of Single Motor Neurons in the Facial Nucleus of the Rat”

Traditionally, sensory processing and motor control have been studied separately, reflecting the belief that sensory and motor streams remain independent until linked via cortical “associative” areas. Although this belief no longer dominates neuroscience, the traditional tendency to continue to

The hindlimb in walking horses: 1. Kinematics and ground reaction forces.

The objective was to study associations between kinematics and ground reaction forces in the hindlimb of walking horses. Video (60 Hz) and force (2000 Hz) data were gathered for 8 strides from each of 5 sound horses during the walk. Sagittal plane kinematics were measured concurrently with the vertical and longitudinal ground reaction forces. The hindlimb showed rapid loading and braking in the initial 10% stride. The stifle, tarsal and coffin joints flexed and the fetlock joint extended during this period of rapid loading. The vertical ground reaction force showed 2 peaks separated by a dip; this pattern was similar to the fetlock joint angle-time graph. Peaks in the longitudinal ground reaction force did not appear to correspond with kinematic events. Total braking impulse was equal to total propulsive impulse over the entire stride. Flexion and extension of the hip were responsible for protraction and retraction of the entire limb. Maximal protraction occurred shortly before the end of swing and maximal retraction occurred during breakover. During the middle part of stance the tarsal joint extended slowly, while the stifle began to flex when the limb was retracted beyond the midstance position at 28% stride. Flexion cycles of the stifle and tarsal joints were well coordinated during the swing phase to raise the distal limb as it was protracted. The results demonstrate a relationship between limb kinematics and vertical limb loading in the hindlimbs of sound horses. Future studies will elucidate the alterations in response to lameness.

Kinematic response to a 70 day training period in trotting Dutch Warmbloods

SummaryTo study the influence of training on the equine locomotor apparatus, the kinematics of 24 almost two‐and‐a‐half‐year‐old Dutch Warmbloods were recorded on a treadmill at the trot (4 m/s) using a modified CODA‐3 apparatus before and after a period of 70 days. In that period, 12 horses of the group were trained for dressage and jumping, while the other 12 were sent to pasture day and night. After 70 days, the hindlimb of the trained horses showed a decreased stance duration, less limb flexion and it reached its maximal protraction earlier in the stride. The stride duration remained the same in the trained horses, while the protraction and retraction range of the forelimb decreased in this group. In the pastured group, however, the horses increased their total range of forelimb movement in the sagittal plane and had a longer swing and stride duration. These results indicate that the definition of ‘training’ is rather relative. The response in the trained group was in agreement with the observation that the majority of horses from this group were trotting with impulsion ‘on the bit’. The pastured group was trotting in a more relaxed way with a longer stride duration and thus a lower stride frequency. In conclusion, this study proved that horses show different responses in their locomotor apparatus depending on the ‘training’ regime received. Using modern gait analysis equipment these differences could be evaluated objectively.

Kinematic detection of superior gait quality in young trotting warmbloods.

This study was conducted to identify objective criteria to select young horses with a good gait, which is a prerequisite for good performance in adult horses. The trot of 24 26-month-old Dutch Warmbloods, led on a loose shank, was subjectively scored by a judge and objectively assessed on a treadmill by using kinematic analysis equipment. It appeared that forelimb and hind limb stride and swing duration, scapula rotation, forelimb maximal fetlock extension, forelimb maximal retraction, hind limb maximal protraction, maximal stifle flexion, and maximal tarsal flexion significantly correlated with a generally accepted gait score in which length, suppleness, and strength are judged. Moreover, the ranking of the individual horses on the basis of gait quality according to their objectively measured kinematic variables was similar to the subjective ranking given by the judge. Thus, a complete picture was obtained of the variables in equine locomotion that determine the quality of the trot in warmbloods.