Risk Reduction of Concussion in Athletes: Do Neck Size or Neck Strength Make a Difference?

ABSTRACT: Medical provider's ability to detect, diagnose, and treat sport-related concussion (SRC) has greatly improved in recent years. Though more is known about the biomechanical forces involved in concussion, it is still uncertain whether there are preventative measures athletes can take to prevent a SRC from occurring. The objective of this review was to determine if either neck size or neck strength is related to a decreased risk of sustaining a SRC. A literature review was conducted on Google Scholar and Ovid MEDLINE for pertinent articles. Findings indicate that isometric neck strength, but not neck size, has been shown to be a predictor for SRC prevention. Formal neck strengthening programs are feasible and lead to decreased SRC risk. Additionally, there may be greater opportunity to increase neck strength in amateur athletes compared to professional. In conclusion, cervical strengthening programs have been shown to be feasible and beneficial for athletes to decrease their risk of sustaining a SRC, though the optimal duration, intensity, and frequency has yet to be determined.

Use of a factor analysis to assess biomechanical factors of American Sign Language in native and non-native signers.

Prior studies suggest that native (born to at least one deaf or signing parent) and non-native signers have different musculoskeletal health outcomes from signing, but the individual and combined biomechanical factors driving these differences are not fully understood. Such group differences in signing may be explained by the five biomechanical factors of American Sign Language that have been previously identified: ballistic signing, hand and wrist deviations, work envelope, muscle tension, and "micro" rests. Prior work used motion capture and surface electromyography to collect joint kinematics and muscle activations, respectively, from ten native and thirteen non-native signers as they signed for 7.5 min. Each factor was individually compared between groups. A factor analysis was used to determine the relative contributions of each biomechanical factor between signing groups. No significant differences were found between groups for ballistic signing, hand and wrist deviations, work envelope volume, excursions from recommended work envelope, muscle tension, or "micro" rests. Factor analysis revealed that "micro" rests had the strongest contribution for both groups, while hand and wrist deviations had the weakest contribution. Muscle tension and work envelope had stronger contributions for native compared to non-native signers, while ballistic signing had a stronger contribution for non-native compared to native signers. Using a factor analysis enabled discernment of relative contributions of biomechanical variables across native and non-native signers that could not be detected through isolated analysis of individual measures. Differences in the contributions of these factors may help explain the differences in signing across native and non-native signers.

Focused ultrasound as an alternative to dry needling for the treatment of tendinopathies: A murine model.

Tendinopathies account for 30% of 102 million annual musculoskeletal injuries occurring annually in the United States. Current treatments, like dry needling, induce microdamage to promote healing but produce mixed success rates. Previously, we showed focused ultrasound can noninvasively create microdamage while preserving mechanical properties in ex vivo murine tendons. This present study compared growth factor, histological, and mechanical effects after focused ultrasound or dry needling treatments in an in vivo murine tendon injury model. Partial Achilles tenotomy was performed in 26 rats. One-week postsurgery, tendons were treated with focused ultrasound (1.5 MHz, 1-ms pulses at 10 Hz for 106 s, p+ = 49 MPa, p- = 19 MPa) or dry needling (30 G needle, 5 fenestrations over 20 s) and survived for 1 additional week. Blood was collected immediately before and after treatment and before euthanasia; plasma was assayed for growth factors. Treated tendons and contralateral controls were harvested for histology or mechanical testing. No differences were found between treatments in release of insulin growth factor 1 and transforming growth factor beta; vascular endothelial growth factor A concentrations were too low for detection. Histologically, focused ultrasound and dry needling tendons displayed localized fibroblast infiltration without collagen proliferation with no detectable differences between treatments. Mechanically, stiffness and percent relaxation of dry needling tendons were lower than controls (p = 0.0041, p = 0.0441, respectively), whereas stiffness and percent relaxation of focused ultrasound tendons were not different from controls. These results suggest focused ultrasound should be studied further to determine how this modality can be leveraged as a therapy for tendinopathies.

Treatment and Management of Work-Related Mild Traumatic Brain Injury in Physical Medicine and Rehabilitation.

ABSTRACT: The purpose of this narrative review was to assess work-related mild traumatic brain injury treatment approaches and outcomes. Literature indicates that incidence of work-related mild traumatic brain injury is high. Ability to return to work after injury is variable, with differences identified across industry sector, mechanisms of injury, sex, and timely treatment and referral. Additional challenges exist in the context of secondary gains (e.g., financial) and the potential for symptom exaggeration. Emerging evidence from studies outside the United States demonstrate the benefits of proactive assessment and treatment at the time of injury. These benefits can be further augmented by early referral to multidisciplinary treatment teams led by physical medicine and rehabilitation physicians. Opportunities for ongoing research and development of strategies to improve treatment, management, and more timely return to work for patients with occupational mild traumatic brain injury are discussed. It is concluded that challenges persist in treatment and management of patients with work-related mild traumatic brain injury as they present unique challenges not seen in those with nonwork-related mild traumatic brain injuries. The unique position of physical medicine and rehabilitation and the skills of physiatrists render them poised to lead multidisciplinary treatment teams for these patients and contribute to the development of a new guideline for return to work, with an emphasis on functional recovery.

Development of a more biofidelic musculoskeletal model with humeral head translation and glenohumeral ligaments.

Computational musculoskeletal modeling is useful for understanding upper extremity biomechanics, especially when in vivo tests are unfeasible. A musculoskeletal model of the upper limb with increased biofidelity was developed by including humeral head translation (HHT) and ligaments. The model was validated and ligament contribution and effect of shoulder (thoracohumeral) elevation on HHT was evaluated. Humerus translated superiorly with increased elevation, with translations closely matching (avg. difference 2.83 mm) previous in vitro studies. HHT and ligament inclusion in the model will improve biomechanical predictions of upper extremity movements and study of conditions, like subacromial impingement, rotator cuff tear, or shoulder instability.

The role of physical arm function and demographic disparities in breast cancer survivors' ability to return to work.

PURPOSE: Ability to return to work (RTW) is an important aspect of breast cancer that is limited for many survivors. With 90% survivorship in the USA, it is imperative that focus shifts toward the improvement of physical arm function to improve survivors' ability to RTW. This narrative review discusses the role of physical arm function and demographic disparities in breast cancer survivor RTW. METHODS: Literature on physical function, arm function, and demographic disparities following breast cancer treatment and their implications for RTW is discussed. RESULTS: The ability to RTW is a key component of recovery for breast cancer survivors, but challenges and inequalities persist. Treatment effects can induce and prolong functional disability, affecting survivors' ability to RTW. These effects may be compounded for survivors whose occupation requires physical arm function. The RTW landscape, including the occupations survivors have, the physical function required for job tasks, and availability of workplace accommodations, is also unclear. Additional demographic disparities (e.g., income, live in rural area) exist, but the extent to which these factors influence RTW is not well understood. More work is needed to understand the compounded impact of treatment effects, demographic disparities, and occupational factors on RTW. Multidisciplinary rehabilitation that includes occupational counseling and exercise is a promising approach, but widespread adoption in the US healthcare model presents an ongoing challenge. Areas for further research are highlighted. CONCLUSION: There is an incomplete understanding of the effects of treatment on physical arm function and the role of demographic disparities on breast cancer survivor RTW.

Movement compensation is driven by the deltoid and teres minor muscles following severe rotator cuff tear.

BACKGROUND: Rotator cuff tears are common in older adults, negatively affecting function. Previous simulation-based studies reported more posterior and superior oriented glenohumeral loading with increased cuff tear severity and task performance, although corresponding muscle compensation strategies are unclear. Our objective is to determine how shoulder muscle forces change with increased rotator cuff tear severity during functional task performance. METHODS: Eight musculoskeletal models of increasing tear severity were developed to represent no rotator cuff tear to massive three-tendon tears. Simulations were performed using each combination of model and kinematics for five functional tasks. Individual muscle forces were averaged for each task and tear severity, then normalized by the sum of the muscle forces across the shoulder. Forces were compared across tear severity and muscle. FINDINGS: For muscle force contribution, interactions between tear severity and muscle and a main effect of muscle were seen for all tasks (P < 0.0001). Middle deltoid increased force contribution by >10% in the greatest tear severity model compared to no cuff tear model for all tasks (all P < 0.0001). Teres minor contribution increased by 7.7%, 5.6%, and 11% in the greatest tear severity model compared to the no cuff tear model for forward reach, axilla wash, and upward reach 105° tasks, respectively (all P < 0.0001). INTERPRETATION: Functional tasks elicit compensatory responses from uninjured muscles following severe cuff tears, notably in middle deltoid and teres minor, leading to posterior-superior glenohumeral loading. The muscles are potential targets for strengthening to avoid injury from sustained increased muscle force.

Therapeutic Ultrasound and Shockwave Therapy for Tendinopathy: A Narrative Review.

ABSTRACT: Tendon injury is prevalent and costly in the United States, comprising 45% of the 66 million musculoskeletal injuries and costing $114 billion annually. Surgical and therapeutic methods, such as arthroscopic surgery, dry needling, and physical therapy, produce mixed success in reintroducing a healing response in tendinopathy due in part to inconsistent dosing and monitoring. Ultrasound is one therapeutic modality that has been shown to noninvasively induce bioeffects in tendon that may help promote healing. However, results from this modality have also been mixed. This review compares the current state of the field in therapeutic ultrasound and shockwave therapy, including low-intensity therapeutic ultrasound, extracorporeal shockwave therapy, and radial shockwave therapy, and evaluates the efficacy in treating tendinopathies with ultrasound. We found that the mixed successes may be attributed to the wide variety of achievable parameters within each broader treatment type and the lack of standardization in measurements and reporting. Despite mixed outcomes, all three therapies show potential as an alternative therapy with lower-risk adverse effects than more invasive methods like surgery. There is currently insufficient evidence to conclude which ultrasound modality or settings are most effective. More research is needed to understand the healing effects of these different therapeutic ultrasound and shockwave modalities.

Automated Tissue Strain Calculations Using Harris Corner Detection.

The elastic modulus, or slope of the stress-strain curve, is an important metric for evaluating tissue functionality, particularly for load-bearing tissues such as tendon. The applied force can be tracked directly from a mechanical testing system and converted to stress using the tissue cross-sectional area; however, strain can only be calculated in post-processing by tracking tissue displacement from video collected during mechanical testing. Manual tracking of Verhoeff stain lines pre-marked on the tissue is time-consuming and highly dependent upon the user. This paper details the development and testing of an automated processing method for strain calculations using Harris corner detection. The automated and manual methods were compared in a dataset consisting of 97 rat tendons (48 Achilles tendons, 49 supraspinatus tendons), divided into ten subgroups for evaluating the effects of different therapies on tendon mechanical properties. The comparison showed that average percent differences between the approaches were 0.89% and -2.10% for Achilles and supraspinatus tendons, respectively. The automated approach reduced processing time by 83% and produced similar results to the manual method when comparing the different subgroups. This automated approach to track tissue displacements and calculate elastic modulus improves post-processing time while simultaneously minimizing user dependency.

Effects of focused ultrasound and dry needling on tendon mechanical properties.

Tendon injuries are extremely common, resulting in mechanically weaker tendons that could lead to tendon rupture. Dry needling (DN) is widely used to manage pain and function after injury. However, DN is invasive and high inter-practitioner variability has led to mixed success rates. Focused ultrasound (fUS) is a non-invasive medical technology that directs ultrasound energy into a well-defined focal volume. fUS can induce thermal ablation or mechanical fractionation, with bioeffect type controlled through ultrasound parameters. Tendons must withstand high physiological loads, thus treatments maintaining tendon mechanical properties while promoting healing are needed. Our objective was to evaluate mechanical effects of DN and 3 fUS parameter sets, chosen to prioritize mechanical fractionation, on Achilles and supraspinatus tendons. Ex vivo rat Achilles and supraspinatus tendons (50 each) were divided into sham, DN, fUS-1, fUS-2, and fUS-3 (n = 10/group). Following treatment, tendons were mechanically tested. Elastic modulus of supraspinatus tendons treated with DN (126.64 ± 28.1 MPa) was lower than sham (153.02 ± 29.3 MPa; p = 0.0280). Stiffness and percent relaxation of tendons treated with DN (Achilles: 114.40 ± 31.6 N/mm; 49.10 ± 6.1%; supraspinatus: 109.53 ± 30.8 N/mm; 50.17 ± 7.6%) were lower (all p < 0.0334) than sham (Achilles: 141.34 ± 20.9 N/mm; 60.30 ± 7.7%; supraspinatus: 135.14 ± 30.2 N/mm; 60.85 ± 15.4%). Modulus of Achilles and supraspinatus tendons treated with fUS-1 (159.88 ± 25.7 MPa; 150.12 ± 22.0 MPa, respectively) were similar to sham (156.35 ± 23.0 MPa; 153.02 ± 29.3 MPa, respectively). These results suggest that fUS preserves mechanical properties better than DN, with fUS-1 performing better than fUS-2 and fUS-3. fUS should be studied further to fully understand its mechanical and healing effects to help evaluate fUS as an alternative, non-invasive treatment for tendon injuries.

Muscle compensation strategies to maintain glenohumeral joint stability with increased rotator cuff tear severity: A simulation study.

Rotator cuff tear (RCT) in older adults may cause decreased muscle forces and disrupt the force balance at the glenohumeral joint, compromising joint stability. Our objective was to identify how increased RCT severity affects glenohumeral joint loading and muscle activation patterns using a computational model. Muscle volume measurements were used to scale a nominal upper limb model's peak isometric muscle forces to represent force-generating characteristics of an average older adult male. Increased RCT severity was represented by systematically decreasing peak isometric muscle forces of supraspinatus, infraspinatus, and subscapularis. Five static postures in both scapular and frontal planes were evaluated. Results revealed that in both scapular and frontal planes, the peak glenohumeral joint contact force magnitude remained relatively consistent across increased RCT severity (average 1.5% and -4.2% change, respectively), and a relative balance of the transverse force couple is maintained even in massive RCT models. Predicted muscle activations of intact muscles, like teres minor, increased (average 5-30% and 4-17% in scapular and frontal planes, respectively) with greater RCT severity. This suggests that the system is prioritizing glenohumeral joint stability, even with severe RCT, and that unaffected muscles play a compensatory role to help stabilize the joint.

Trends and advancements in shoulder biomechanics research.

The 12th International Shoulder Group (ISG) Conference was held at Mayo Clinic in Rochester, Minnesota, USA, from August 12-13, 2018, and was hosted by Dr. Melissa (Missy) Morrow of Mayo Clinic and Dr. Meghan Vidt of Pennsylvania State University. This conference was held as a satellite conference to the annual 2018 American Society of Biomechanics Conference. This Editorial accompanies the Special Issue of the Journal of Electromyography and Kinesiology, and contains a selection of the work presented during the 12th Meeting of the ISG. Fourteen full-length articles describe advancements in shoulder research relevant to both basic science and clinical outlets. The work presented herein spans the research areas of methodology, mechanistic understanding, and clinical management. These areas are synergistic and equally important to propel the field forward and enhance impact. These manuscripts reinforce the dedication of the ISG and its members and showcase the ongoing drive toward translational application of these concepts across the common themes of rotator cuff, muscle, wheelchair & ergonomics, and methods & modeling. Highlights of each of the special issue publications are described within the context of the current trends in shoulder research and areas for further advancement.

Upper extremity biomechanics in native and non-native signers.

BACKGROUND: Individuals fluent in sign language (signers) born to non-signing, non-deaf parents (non-natives) may have a greater injury risk than signers born to signing, deaf parents (natives). A comprehensive analysis of movement while signing in natives and non-natives has not been completed and could provide insight into the greater injury prevalence of non-natives. OBJECTIVE: The objective of this study was to determine differences in upper extremity biomechanics between non-natives and natives. METHODS: Strength, 'micro' rests, muscle activation, ballistic signing, joint angle, and work envelope were captured across groups. RESULTS: Non-natives had fewer rests (p = 0.002) and greater activation (p = 0.008) in non-dominant upper trapezius. For ballistic signing, natives had greater anterior-posterior jerk (p = 0.033) and for joint angle, natives demonstrated greater wrist flexion-extension range of motion (p = 0.040). Natives also demonstrated greater maximum medial-lateral (p = 0.015), and greater minimum medial-lateral (p = 0.019) and superior-inferior (p = 0.027) positions. CONCLUSIONS: We observed that natives presented with more rests and less activation, but greater ballistic tendencies, joint angle, and envelope compared to non-natives. Additional work should explore potential links between these outcomes and injury risk in signers.

Glenohumeral joint loading is impacted by rotator cuff tear severity during functional task performance.

BACKGROUND: Rotator cuff tear is a common musculoskeletal injury, negatively affecting shoulder function. Rotator cuff tear severity ranges from small to massive tears, but it is unclear how tear severity affects glenohumeral joint loading and how changes contribute to secondary injury. This study's objective was to determine how glenohumeral joint contact force changes with tear severity during functional task performance using computational models. METHODS: Eight models of increasing tear severity were developed, ranging from no rotator cuff tear to massive three-tendon tears. Simulations were performed using models representing increasing tear severity and kinematics for five functional tasks (n = 720 simulations). For each task, magnitude and orientation of peak resultant joint contact force for each tear severity was identified, then compared to the no rotator cuff tear model. FINDINGS: For all tasks, compared to the no rotator cuff tear model, joint contact force magnitude decreased 9.5% on average with infraspinatus involvement, then plateaued at 20.8% average decrease with subscapularis involvement. Projected orientation of peak joint contact force vector was located more superior in the glenoid with increased tear severity, with significant changes (p < 0.0003) for all tasks with infraspinatus involvement. INTERPRETATION: Decreased magnitude and superior orientation of joint contact force suggest fewer intact muscles contribute to force distribution across the joint, although more work is needed characterizing associated compensation strategies. All force vectors remained oriented within the glenoid rim for all tasks and models, suggesting the system prioritizes joint stability. This work identifies how joint contact force changes with rotator cuff tear severity.

Focused Ultrasound Mechanical Disruption of Ex Vivo Rat Tendon.

Around 30 million tendon injuries occur annually in the U.S. costing $ 114 billion. Conservative therapies, like dry needling, promote healing in chronically injured tendons by inducing microdamage but have mixed success rates. Focused ultrasound (fUS) therapy can noninvasively fractionate tissues through the creation, oscillation, and collapse of bubbles in a process termed histotripsy; however, highly collagenous tissues, like tendon, have shown resistance to mechanical fractionation. This study histologically evaluates whether fUS mechanical disruption is achievable in tendons. Ex vivo rat tendons (45 Achilles and 44 supraspinatus) were exposed to 1.5-MHz fUS operating with 0.1-10 ms pulses repeated at 1-100 Hz for 15-60 s with peak positive pressures <89 MPa and peak negative pressures <26 MPa; other tendons were exposed to dry needling or sham. Immediately after treatment, tendons were flash-frozen and stained with hematoxylin and eosin (H&E) or alpha-nicotinamide adenine dinucleotide diaphorase ( α -NADH-d) and evaluated by two reviewers blinded to the exposure conditions. Results showed successful creation of bubbles for all fUS-treated samples; however, not all samples showed histological injury. When the injury was detected, parameter sets with shorter pulses (0.1-1 ms), lower acoustic pressures, or reduced treatment times showed mechanical disruption in the form of fiber separation and fraying with little to no thermal injury. Longer pulses or treatment times showed a combination of mechanical and thermal injury. These findings suggest that mechanical disruption is achievable in tendons within a small window of acoustic parameters, supporting the potential of fUS therapy in tendon treatment.

Comparison between dry needling and focused ultrasound on the mechanical properties of the rat Achilles tendon: A pilot study.

In the U.S., approximately 14 million tendon and ligament injuries are reported each year. Dry needling (DN) is a conservative treatment introduced to alleviate pain and restore function; however, it is invasive and has mixed success. Focused ultrasound (fUS) is a non-invasive technology that directs ultrasound energy into a well-defined focal volume. fUS induces thermal and/or mechanical bioeffects which can be controlled by the choice of ultrasound parameters. fUS could be an alternative to DN for treatment of tendon injuries, but the bioeffects must be established. Thus, the purpose of this pilot study was to compare the effect of DN and fUS on the mechanical properties and cell morphology of 30 ex vivo rat Achilles tendons. Tendons were randomly assigned to sham, DN, or fUS, with 10 tendons per group. Within each group, 5 tendons were evaluated mechanically, and 5 tendons were analyzed histologically. Elastic modulus in the DN (74.05 ± 15.0 MPa) group was significantly lower than sham (149.84 ± 59.1 MPa; p = 0.0094) and fUS (128.84 ± 28.3 MPa; p = 0.0453) groups. Stiffness in DN (329.05 ± 236.8 N/mm; p = 0.0034) and fUS (315.26 ± 68.9 N/mm; p = 0.0027) groups were significantly lower than sham (786.10 ± 238.7 N/mm) group. Histologically, localized necrosis was observed in 3 out of 5 tendons exposed to fUS, with surrounding tissue unharmed; no evidence of cellular injury was observed in DN or sham groups. These results suggest that fUS preserves the mechanical properties of tendon better than DN. Further studies are needed to evaluate fUS as an alternative, noninvasive treatment modality for tendon injuries.

Upper extremity and trunk body segment parameters are affected by BMI and sex.

Although body mass index (BMI) relates to body segment parameters (BSPs), unknowns persist over whether: 1) BSPs relate to BMI group classifications, 2) sex influences BMI/BSP relationships, and 3) simple anthropometric measures sufficiently predict BSPs. Dual energy X-ray absorptiometry (DXA) scans and anthropometric measures were obtained from 76 participants (33M, 43F) of varying body composition. Trunk, neck and head (TNH), arm, forearm and hand masses were obtained from DXA scans and center of mass locations (COM) estimated from geometric models. Groups with larger BMIs had lesser hand and forearm mass (%total body mass; p<0.001) and greater TNH mass (p=0.014). Males had greater hand, forearm, and arm masses (p<0.05). TNH COM was inferior in groups with larger BMI (p<0.01) and in males (p=0.006). In females, arm COM was distal in Obese II/III versus Normal (p=0.024). Two sets of linear models were created to predict BSPs; a simplified set with only BMI, height, weight, sex and mass potential predictors and a complex set with additional anthropometric measures. Complex arm and TNH mass models (arm R2=0.43, TNH R2=0.61) explained more variance than simplified models (arm R2=0.1, TNH R2=0.33). Complex hand mass, forearm mass and TNH COM models had smaller R2 increases versus simplified models (hand=0.05, forearm=0.06, TNH=0.08). Explained variance in forearm COM (R2=0.2) and arm COM (R2=0.27) complex models was low, suggesting a constant may provide reasonable estimates. Certain BSPs can be estimated using simplified measures, whereas prediction of other BSPs markedly improves if additional anthropometric measures are included.

The Modified Strain Index: A Composite Measure of Injury Risk for Signers.

Up to 81% of individuals who are fluent in sign language (signers) report pain. Non-native signers (with non-signing, non-deaf parents) report greater pain than natives (≥1 signing, deaf parent). The goal of this study was to develop a composite measure of injury risk (the modified Strain Index for signers) based on previously identified biomechanics unique to signers and examine scores across sub-groups of natives and non-natives. Non-natives were hypothesized to have greater pain and higher composite scores than natives. Ten natives and 15 non-natives used a numeric scale to rate pain while signing. Measures included 'micro' rests, muscle activation, ballistic signing, non-neutral joint angle, and work envelope. Descriptive statistics were used to create categorical ratings and backward elimination multiple linear regression to establish rank order of the biomechanical tasks. Participant performance was rated, and the product of the multipliers across tasks created a score. Pain intensity was associated with the composite score (r = 0.46; p = 0.02), however there was no difference between natives (score = 13.39 ± 3.1) and non-natives (score = 19.55 ± 4.7; p = 0.34). This work presents an approach to incorporate multiple biomechanical factors into a single, composite measure unique to signers, however further evidence-based adjustments are needed to enhance its robustness.

A simple joint control pattern dominates performance of unconstrained arm movements of daily living tasks.

A trailing joint control pattern, during which a single joint is rotated actively and the mechanical effect of this motion is used to move the other joints, was previously observed during simplified, laboratory-based tasks. We examined whether this simple pattern also underlies control of complex, unconstrained arm movements of daily activities. Six tasks were analyzed. Using kinematic data, we estimated motion of 7 degrees of freedom (DOF) of the shoulder, elbow, and wrist, and the contribution of muscle and passive interaction and gravitational torques to net torque at each joint. Despite task variety, the hand was transported predominantly by shoulder and elbow flexion/extension, although shoulder external/internal rotation also contributed in some tasks. The other DOF were used to orient the hand in space. The trailing pattern represented by production of net torque by passive torques at the shoulder or elbow or both was observed during the biggest portion of each movement. Net torque generation by muscle torque at both joints simultaneously was mainly limited to movement initiation toward the targets and movement termination when returning to the initial position, and associated with needing to overcome gravity. The results support the interpretation of previous studies that prevalence of the trailing pattern is a feature of skillful, coordinated movements. The simplicity of the trailing pattern is promising for quantification of dyscoordination caused by motor disorders and formulation of straightforward instructions to facilitate rehabilitation and motor learning.

The influence of mastectomy and reconstruction on residual upper limb function in breast cancer survivors.

PURPOSE: Breast cancer survivorship is common (90% of women survive 5 or more years), but many women are not able to return to full function and well-being after treatment due to functional limitations, persistent pain, and inability to perform daily activities. Since each surgical reconstructive option (e.g., autologous tissue flaps versus implants) can impact shoulder and arm function differently, it is important to understand how shoulder and upper limb strength, mobility, and function are influenced by the type of surgical intervention. Efforts can then focus on prehabiliation strategies to prevent the onset of limitations and on developing rehabilitation protocols that directly target shortcomings. METHODS: The current paper presents a review summarizing how shoulder and upper limb function may be affected by surgical mastectomy and breast reconstruction. RESULTS: Mastectomy and breast reconstruction with implants or autologous tissues present different functional outcomes for patients. Each surgical procedure is associated with unique sequelae derived from the tissues and procedures associated with each surgery. Characterizing the specific functional outcomes associated with each surgical approach will promote the development of targeted rehabilitation strategies that can be implemented into a multidisciplinary treatment planning pathway for breast cancer patients. CONCLUSIONS: Surgical treatments for breast cancer, including mastectomy and breast reconstruction, can have negative effects. Focused efforts are needed to better understand treatment-specific effects so that targeted rehabilitation can be developed to improve patient function, QoL, and ability to return to work and life activities post-breast cancer.