Pressure Sensors for Evaluating Hand Grasp and Pinch.

This study addresses the need for highly sensitive tools to evaluate hand strength, particularly grasp and pinch strength, which are vital for diagnosing and rehabilitating conditions affecting hand function. Current devices like the Jamar dynamometer and Martin Vigorimeter, although reliable, fail to measure extremely low force or pressure values required for individuals with severe hand impairments. This research introduces a novel device, a modified Martin Vigorimeter, utilizing an ultra-soft latex chamber and differential pressure measurement to detect minute pressure changes, thus significantly enhancing sensitivity. The device offers a cost-effective solution, making advanced hand strength evaluation more accessible for clinical and research applications. Future research should validate its accuracy across diverse populations and settings, exploring its broader implications for hand rehabilitation and occupational health.

Metacarpophalangeal hyperextension in trapeziometacarpal osteoarthritis: Relationship to first metacarpal head shape, and clinical impact.

PURPOSE: The aim of this study was to determine whether the shape of the first metacarpal head influences metacarpophalangeal hyperextension, and to evaluate the influence of metacarpophalangeal hyperextension on hand pain and function in patients with trapeziometacarpal osteoarthritis. METHODS: 362 patients with painful basal thumb osteoarthritis were evaluated over a 2-year period. Pain rating on a visual analog scale, trapeziometacarpal and metacarpophalangeal motion, and grip and pinch strength were evaluated. The shape of the metacarpal head was assessed on strict lateral radiographs using the "A/r" ratio. RESULTS: Round metacarpal heads had significantly greater and more frequent metacarpophalangeal hyperextension than flat heads (28° vs. 8°, and 78% vs. 29%). Metacarpophalangeal hyperextension adversely impacted trapeziometacarpal motion in antepulsion (27° vs. 32°), abduction (25° vs. 30°) and pinch strength (3.6 vs. 4.6 KgF). CONCLUSION: Our findings indicate that the shape of the metacarpal head influences metacarpophalangeal hyperextension in trapeziometacarpal osteoarthritis. Metacarpophalangeal hyperextension adversely impacted pinch strength and trapeziometacarpal motion. LEVEL OF EVIDENCE: Level IV, Retrospective case series.

The reliability of a Biometrics device as a tool for assessing hand grip and pinch strength, in a Polish cohort-A prospective observational study.

The aim of the study was to assess the external and internal compatibility of the Biometrics E-LINK EP9 evaluation system device in the area of hand grip and pinch strength in the Polish population. The testing of hand grip and pinch strength was carried out among 122 healthy students. Two examiners performed hand grip and pinch strength measurements with a Biometrics E-LINK EP9 evaluation system device. Measurements were made for the right and left hands. The same people were tested again two weeks later, under the same conditions. The scores of one rater on the first and second tests were compared for reproducibility, and the scores of the two raters were compared to assess the reliability of the instrument. The measurements were found to be highly consistent both between the investigators and between the tests in the hand grip dynamometer test. The findings show high values of the Pearson's correlation coefficient equal or close to 1, as well as the interclass correlation coefficient (ICC) >0.9. Analysis of pinch strength measurements performed using the pinchmeter also found high values of the Pearson's correlation coefficient close to 1, as well as the interclass correlation coefficient >0.9; this reflects high agreement between the measurements performed by two investigators as well as assessments performed by one investigator at time intervals. These findings were confirmed by analyses performed using Bland-Altman plots. The measurements made with the Biometrics E-link EP9 evaluation system show high internal and external consistency in hand grip and pinch strength assessment. Biometrics E-link EP9 can be recommended for daily clinical practice.

Carpal tunnel syndrome prediction with machine learning algorithms using anthropometric and strength-based measurement.

OBJECTIVES: Carpal tunnel syndrome (CTS) stands as the most prevalent upper extremity entrapment neuropathy, with a multifaceted etiology encompassing various risk factors. This study aimed to investigate whether anthropometric measurements of the hand, grip strength, and pinch strength could serve as predictive indicators for CTS through machine learning techniques. METHODS: Enrollment encompassed patients exhibiting CTS symptoms (n = 56) and asymptomatic healthy controls (n = 56), with confirmation via electrophysiological assessments. Anthropometric measurements of the hand were obtained using a digital caliper, grip strength was gauged via a digital handgrip dynamometer, and pinch strengths were assessed using a pinchmeter. A comprehensive analysis was conducted employing four most common and effective machine learning algorithms, integrating thorough parameter tuning and cross-validation procedures. Additionally, the outcomes of variable importance were presented. RESULTS: Among the diverse algorithms, Random Forests (accuracy of 89.474%, F1-score of 0.905, and kappa value of 0.789) and XGBoost (accuracy of 86.842%, F1-score of 0.878, and kappa value of 0.736) emerged as the top-performing choices based on distinct classification metrics. In addition, using variable importance calculations specific to these models, the most important variables were found to be wrist circumference, hand width, hand grip strength, tip pinch, key pinch, and middle finger length. CONCLUSION: The findings of this study demonstrated that wrist circumference, hand width, hand grip strength, tip pinch, key pinch, and middle finger length can be utilized as reliable indicators of CTS. Also, the model developed herein, along with the identified crucial variables, could serve as an informative guide for healthcare professionals, enhancing precision and efficacy in CTS prediction.

Manual Dexterity Predictors of Artificial Urinary Sphincter Success.

OBJECTIVE: To determine better in-office measures for artificial urinary sphincter outcomes, we investigated the ability of preoperative timed peg-transfer, pinch strength, grip strength, and Disabilities of the Arm Shoulder and Hand Outcome questionnaire in predicting postoperative satisfaction, confidence, and ease of use of artificial urinary sphincter placement for stress urinary incontinence. MATERIALS AND METHODS: A timed 9-hole peg test, pinch and grip strength assessment, and upper extremity questionnaire were administered during the preoperative visit before sphincter placement. In addition to standard preoperative workup, short-form International Consultation of Incontinence Questionnaire and physician handshake were recorded. Activation occurred 6 weeks after surgery along with assessment of adequacy of pump placement. Three months from surgery a repeat incontinence questionnaire and a survey measuring satisfaction, difficulty of use, and confidence were given. Correlation between preoperative assessment variables and the postoperative questionnaire was assessed. RESULTS: Thirty-nine patients were included. Average age and body mass index were 68.8 years and 28.8 kg/m2, respectively. Prior prostatectomy accounted for 92.3% of patients, and 46.2% had prior pelvic radiation. Postoperatively, 59.0% of patients were very satisfied; 64.1% of patients reported no difficulty of use; 53.8% felt confidence within 1 day; and 66.7% had much better bladder control. Average pad improvement count was 5.3. Pinch test was associated with satisfaction (P = .011) while peg test was associated with confidence (P = .049). Handshake and upper extremity questionnaire were not significant. CONCLUSION: The pinch and 9-hole peg transfer tests are cost-effective and easily performed adjuncts that could be used during artificial urinary sphincter evaluation for patients with unclear manual functional status.

Exploratory analysis using machine learning algorithms to predict pinch strength by anthropometric and socio-demographic features.

Objectives. This study examines the role of different machine learning (ML) algorithms to determine which socio-demographic factors and hand-forearm anthropometric dimensions can be used to accurately predict hand function. Methods. The cross-sectional study was conducted with 7119 healthy Iranian participants (3525 males and 3594 females) aged 10-89 years. Seventeen hand-forearm anthropometric dimensions were measured by JEGS digital caliper and a measuring tape. Tip-to-tip, key and three-jaw chuck pinches were measured using a calibrated pinch gauge. Subsequently, 21 features pertinent to socio-demographic factors and hand-forearm anthropometric dimensions were used for classification. Furthermore, 12 well-known classifiers were implemented and evaluated to predict pinches. Results. Among the 21 features considered in this study, hand length, stature, age, thumb length and index finger length were found to be the most relevant and effective components for each of the three pinch predictions. The k-nearest neighbor, adaptive boosting (AdaBoost) and random forest classifiers achieved the highest classification accuracy of 96.75, 86.49 and 84.66% to predict three pinches, respectively. Conclusions. Predicting pinch strength and determining the predictive hand-forearm anthropometric and socio-demographic characteristics using ML may pave the way to designing an enhanced tool handle and reduce common musculoskeletal disorders of the hand.

Management of the capsule in trapeziometacarpal joint implant arthroplasty: resection versus repair.

We compared the effects of capsule resection versus capsule suturing in patients treated with a dual-mobility trapeziometacarpal joint prosthesis. We included 131 patients with capsular resection and 57 patients with repair. The mean scores for pain and the brief Michigan Hand Outcomes Questionnaire were similar between the groups preoperatively and at 6 weeks and 1 year postoperatively. Mean key pinch strength was also similar in both groups before surgery and at 1 year, but higher in the capsular resection than in the suture group at 6 weeks. The incidence of complications reported throughout the 1-year postoperative period was not significantly different between the groups. One implant in the capsular resection group was revised for reasons most likely unrelated to capsule management. We conclude that the capsule can be safely resected during trapeziometacarpal joint implant arthroplasty.Level of evidence: III.

Assessment and treatment of nonsurgical thumb carpometacarpal joint osteoarthritis: A modified Delphi-based consensus paper of the American Society of Hand Therapists.

BACKGROUND: While the literature is abundant on hand therapy assessment and treatment of nonsurgical thumb carpometacarpal (CMC) osteoarthritis (OA), clarity and uniformity are meager, making it a desirable diagnosis to establish expert consensus. PURPOSE: This study aimed to ascertain if consensus exists for the assessment and treatment of nonsurgical management of thumb CMC OA in the hand therapy clinical setting. STUDY DESIGN: This was a consensus paper via the modified Delphi approach. METHODS: A modified Delphi method was used to determine consensus among an expert panel, including hand therapists and hand surgeons, via two online surveys. A consensus paper steering committee (from the American Society of Hand Therapist's research division) designed the surveys and analyzed responses. Consensus was established as 75% agreement among the expert panel. Demographic information was collected from the expert panel. RESULTS: The expert panel included 34 hand therapists and seven hand surgeons. The survey response rates were 93.6% for the first survey and 90.2% for the second survey. Consensus recommendations were classified according to the World Health Organization categorization. These included evaluating the body structures for clinical signs/clinical testing and body functions for pain, range of motion for palmar abduction, radial abduction, opposition, and thumb metacarpal phalangeal flexion/extension, and grip and tripod pinch strength. Further consensus recommendations were for the assessment of function using a region-specific, upper extremity patient-reported outcome measure (activity and participation), environmental factors, outcome expectation, and illness perception within the patient's unique environmental and social contexts. Treatment recommendations included the use of an orthosis during painful activities, a dynamic stability program (stable C posture, release of tight adductors, and strengthening of stabilizers), patient education, joint protection techniques, adaptive equipment, and functional-based intervention. CONCLUSIONS: The findings describe the consensus of a group of experts and provide a clinical reference tool on the hand therapy assessment and treatment of nonsurgical thumb CMC joint OA.

Force-amplifying implant to improve key pinch strength in tendon transfer surgery: Cadaver model proof-of-concept.

The brachioradialis (BR) to flexor pollicis longus (FPL) tendon transfer surgery is a common procedure used to restore key pinch grip for incomplete spinal cord injury patients. However, the procedure only restores 22% of the physiological grip strength, which is important for successfully grasping objects and minimizing fatigue. The purpose of this study was to evaluate the efficacy of using a novel force-amplifying pulley implant to modify the standard BR to FPL tendon transfer surgery to improve key pinch grip strength in a human cadaver forearm model. A total of eight cadaveric specimens were mounted onto a custom testbed where a torque-controlled motor actuated the BR tendon to produce key pinch grip. In each cadaver, two experimental groups were examined: a standard and an implant-modified BR to FPL tendon transfer surgery. A force sensor mounted to the thumb recorded isometric key pinch grip forces over a range of input BR forces (2 N-25 N) applied in a ramp-and-hold protocol. Across the range of input BR forces, the average improvement in key pinch grip strength in the implant-modified surgery compared to the standard surgery was 58 ± 7.1% (ranging from 41% to 64% improvement). Throughout the experiments, we observed that the implant did not hinder the movement of the BR or FPL tendons. These results suggest that a BR to FPL tendon transfer surgery utilizing a force-amplifying pulley implant to augment force transmission can provide additional functional strength restoration over the standard procedure that directly sutures two tendons together.

A quantitative measurement of trapeziometacarpal joint pressure using a cadaveric model of lateral pinch.

Trapeziectomy is performed for trapeziometacarpal (TMC) arthritis but decreased lateral pinch strength is a major source of discomfort after the surgery. The magnitude of the decrease is unclear, however, and how the pressure changes in the TMC joint is unknown. To investigate this relationship, we designed a cadaveric study to measure TMC joint pressure using a lateral pinch model, and quantitatively evaluated the effect of trapeziectomy on the pressure measurements. For 10 cadaveric forearms, physiologic forces were applied across the thumb TMC joint by loading five tendons, thereby simulating lateral pinch. Using pressure sensors, we measured the lateral pinch pressure and TMC joint pressure, which averaged 10.1 (range, 4.2-16.2) kg/cm2 and 2.0 (range, 0.8-4.4) kg/cm2 , respectively. A significant correlation between the measurements was found, with an average ratio of 19% (range, 10%-27%). After trapeziectomy and interposition of the tendon ball using flexor carpi radialis, the pressure measurements were repeated under the same conditions. Significant changes were found, which averaged 5.1 (range, 1.7-10.7) kg/cm2 for lateral pinch pressure and 15.0 (range, 5.6-25.6) kg/cm2 for TMC joint pressure. In conclusion, TMC joint pressure could be measured as the ratio relative to lateral pinch pressure using a cadaveric model. After trapeziectomy, the lateral pinch strength decreased, whereas the TMC joint pressure increased.

Diabetic Peripheral Neuropathy Affects Pinch Strength and Hand Dexterity in Elderly Patients.

Objective: Diabetic peripheral neuropathy (DPN) is one of the most common chronic complications of diabetes, leading to disability and decreased quality of life. In past research and clinical studies, the lower limb function of DPN patients was often the principal subject of research, with little attention given to the upper limb and hand. Our goal was to assess and compare hand function between elderly diabetic patients with DPN and without DPN. Methods: A total of 52 diabetic patients were registered and underwent hand function assessments and electrodiagnostic tests. Dynamometer, pinch meter, Semmes Weinstein monofilaments, and the Purdue Pegboard Test (PPT) were used to assess the patients' grip strength, pinch strength, tactile sensory threshold, and hand dexterity. Results: Compared with the non-DPN group, the elderly DPN group showed worse thumb-middle fingertip pinch strength and thumb-little fingertip pinch strength in the dominant hand (3.50 (2.50, 4.25) vs. 4.50 (3.00, 5.00), p = 0.019; 1.50 (1.00, 2.00) vs. 2.50 (2.00, 3.00), p < 0.001); the elderly DPN group displayed worse thumb-middle fingertip pinch strength, thumb-ring fingertip pinch strength, and thumb-little fingertip pinch strength in the nondominant hand (3.50 (2.00, 4.50) vs. 4.00 (3.00, 5.00), p = 0.013; 2.50 (1.25, 3.00) vs. 3.00 (2.50, 3.50), p = 0.033; 1.00 (0.75, 2.25) vs. 2.50 (2.00, 2.50), p < 0.001). The elderly DPN group scored lower than the non-DPN group on the PPT test of assembly (13.96 ± 5.18 vs. 16.96 ± 4.61, t = 2.212, p = 0.032). Conclusion: Motor function limitation is the principal hand dysfunction in elderly patients with DPN, which is mainly manifested as a decline in fingertip pinch strength and a decrease in hand dexterity. This trial is registered with Clinical Trial Registry no. ChiCTR1900025358.

Role and effectiveness of complex and supervised rehabilitation on overall and hand function in systemic sclerosis patients-one-year follow-up study.

The aim of this study was to estimate the long-term results of complex and supervised rehabilitation of the hands in systemic sclerosis (SSc) patients. Fifty-one patients were enrolled in this study: 27 patients (study group) were treated with a 4-week complex, supervised rehabilitation protocol. The control group of 24 patients was prescribed a home exercise program alone. Both groups were evaluated at baseline and after 1-, 3-, 6-, and 12-months of follow-up with the Disability of the Arm, Shoulder and Hand Questionnaire (DAHS) as the primary outcome, pain (VAS-visual analog scale), Cochin Hand Function Scale (CHFS), Health Assessment Questionnaire Disability Index (HAQ-DI), Scleroderma-HAQ (SHAQ), range of motion (d-FTP-delta finger to palm, Kapandji finger opposition test) and hand grip and pinch as the secondary outcomes. Only the study group showed significant improvements in the DASH, VAS, CHFS and SHAQ after 1, 3 and 6 months of follow-up (P = 0.0001). Additionally, moderate correlations between the DASH, CHFS and SHAQ (R = 0.7203; R = 0.6788; P = 0.0001) were found. Complex, supervised rehabilitation improves hand and overall function in SSc patients up to 6 months after the treatment but not in the long term. The regular repetition of this rehabilitation program should be recommended every 3-6 months to maintain better hand and overall function.

Clinical and electrophysiological examination of pinch strength in patients with amyotrophic lateral sclerosis.

BACKGROUND: The split-hand concept has highlighted the preferential wasting of the thenar side of the hand in amyotrophic lateral sclerosis (ALS). Our objective is to re-explore pinch grip strength to assess whether it has the potential to be a practical biomarker of ALS. METHODS: We measured different pinch grip strengths (thumb, index, and fifth) using a pinch gauge from both hands of 54 ALS patients and correlated this with the Medical Research Council (MRC) score, the upper-limb component of the revised ALS Functional Rating Scale - Revised (ALSFRS-R) score, and compound muscle action potentials (CMAPs) that comprise the split-hand index. RESULTS: Pinch grip strength using any of the three fingers showed a positive correlation with its corresponding CMAP, MRC grading, and upper-limb ALSFRS-R score. The thumb pinch showed the strongest correlation with the split-hand index and MRC grading. CONCLUSIONS: Pinch grip strength test using a simple gauge deserves further study as a potentially practical biomarker of ALS.

Relationship between ultrasonographic hand muscle thickness measurements and muscle strength following median or ulnar nerve reconstruction.

INTRODUCTION: The aim of this study was to assess the relationship between ultrasonographic hand muscle thickness measurements and hand muscle strength in patients who underwent median or ulnar nerve reconstruction. METHODS: In this prospective, cross-sectional study, intrinsic hand muscle thicknesses were measured using ultrasound with a 4- to 13-MHz linear-array probe. Measurements of hand strength were performed using a dynamometer and a pinchmeter. RESULTS: In the median nerve group (n = 11), a moderate correlation (r = 0.694; P = .018) was observed between lateral pinch strength and transverse thenar thickness. In the ulnar nerve group (n = 11), longitudinal thenar thickness below the flexor pollicis longus tendon was moderate to highly correlated with pinch and handgrip strengths (r = 0.726-0.893; P < .05); whole transverse thenar thickness was moderate to highly correlated with pinch strengths (r = 0.724-0.836; P < .05). DISCUSSION: Sonographic measurements of intrinsic hand muscle thickness may be a useful tool for the assessment and follow-up of patients with median or ulnar nerve injury.

Effect of a Novel Perturbation-Based Pinch Task Training on Sensorimotor Performance of Upper Extremity for Patients With Chronic Stroke: A Pilot Randomized Controlled Trial.

OBJECTIVE: To investigate the effects of perturbation-based pinch task training on the sensorimotor performance of the upper extremities of patients with chronic stroke via a novel vibrotactile therapy system. DESIGN: A single-blinded randomized controlled trial. SETTING: A university hospital. PARTICIPANTS: Patients with chronic stroke (N=19) randomly assigned into either an experimental group or a control group completed the study. INTERVENTIONS: In addition to 10 minutes of traditional sensorimotor facilitation, each participant in the experimental group received 20 minutes of perturbation-based pinch task training in each treatment session, and the controls received 20 minutes of task-specific motor training twice a week for 6 weeks. MAIN OUTCOME MEASURES: The scores for the primary outcome, Semmes-Weinstein monofilament (SWM), and those for the secondary outcomes, Fugl-Meyer Assessment (FMA), amount of use, quality of movement (QOM) on the Motor Activity Log (MAL) scale, and box and block test (BBT), were recorded. All outcome measures were recorded at pretreatment, post treatment, and 12-week follow-up. RESULTS: There were statistically significant between-group differences in the training-induced improvements revealed in the SWM results (P=.04) immediately after training and in the BBT results (P=.05) at the 12-week follow-up. The changes in muscle tone and in the QOM, SWM, and BBT scores indicated statistically significant improvements after 12 sessions of treatment for the experimental group. For the control group, a significant statistical improvement was found in the wrist (P<.001) and coordination (P=.01) component of the FMA score. CONCLUSIONS: This study indicated that the perturbation-based pinch task training has beneficial effects on sensory restoration of the affected thumb in patients with chronic stroke.

Validation of a new hand function outcome measure in individuals with Charcot-Marie-Tooth disease.

The symptomatology of Charcot-Marie-Tooth (CMT) disease mainly involves the feet and the hands. To date, there is no consensus on how to evaluate hand function in CMT. The aim of this study is to correlate the data of the engineered glove Hand Test System (HTS) with specific tests and the CMT examination score (CMTES). We analyzed 45 patients with the diagnosis of CMT using HTS, which measures the hand dexterity by specific sequences performed at maximum velocity. We completed the evaluation with the CMTES, tripod pinch and hand grip strength tested by a dynamometer, thumb opposition test (TOT), and Sollerman Hand function test (SHFT), and we conducted a test-retest with 20 normal subjects. Finger tapping (FT) and index-medium-ring-little (IMRL) sequence showed a significant correlation with CMTES (FT: dominant hand (DH): P = .036; non-dominant hand (NDH): P = .033; IMRL: DH: P = .009; NDH: P = .046). TOT correlated with CMTES significantly in both hands (P < .0001). tripod pinch showed a statistically significant correlation with CMTES (DH: P = .002; NDH: P = .005). Correlation between the hand grip and CMTES was significant only in DH (DH: P = .002). SHFT had a significant correlation with the CMTES (DH: P = .002). Test-retest showed a good reliability. HTS parameters correlate with CMTES confirming that this tool is sensitive to the hand deficits. In conclusion, we can state that HTS is a good, simple to use, and objective instrument to evaluate the hand function of CMT patients, but more studies on responsiveness and sensitivity are needed.

Optimizing hand-function patient outcome measures for inclusion body myositis.

Inclusion body myositis is the most commonly acquired myopathy after the age of 45. The slowly progressive and heterogeneous disorder is a challenge for measuring clinical trial efficacy. One current method for measuring progression utilizes the Inclusion Body Myositis-Functional Rating Scale. We have found that the upper extremity domain scores in the Inclusion Body Myositis-Functional Rating Scale do not consistently change until there is extreme loss of grip and finger flexor strength. Therefore, we performed a cross-sectional observational study of 83 inclusion body myositis patients and 38 controls recruited at the 2019 Annual Patient Conference of The Myositis Association. We evaluated new Inclusion Body Myositis Patient-Reported Outcome measures for upper extremity function modified from the NIH Patient-Reported Outcomes Measurement Information System as well as pinch and grip strength. We found that Patient-Reported Outcome measures hand-function have a higher correlation with pinch and grip strength than the Inclusion Body Myositis-Functional Rating Scale.

Upper Extremity Muscle Strength in Children With Unilateral Spastic Cerebral Palsy: A Bilateral Problem?

OBJECTIVE: The objective was to investigate whether muscle strength in the nonaffected and affected upper extremities (UEs) in children (7-12 years) with unilateral spastic cerebral palsy (USCP) differs from that in children with typical development (TD). METHODS: A cross-sectional study design was used. Isometric arm strength (wrist flexion, wrist extension with flexed and extended fingers, elbow flexion/extension) was assessed in 72 children (mean age = 9.3 [SD = 1.9] years) with USCP, and isometric grip/pinch strength was assessed in 86 children (mean age = 9.3 [SD = 1.8] years) with USCP. Arm/grip/pinch strength was assessed in 120 children (mean age = 9.5 [SD = 1.7] years) with TD. Arm strength was measured with a hand-held dynamometer, and grip/pinch strength was measured with a calibrated, modified (digitized) grip dynamometer and a pinch meter. The nonaffected UE of children with USCP was compared with the preferred UE of children with TD because both sides represent the preferred UE. The affected UE was compared with the nonpreferred UE of children with TD, as both sides represent the nonpreferred UE. RESULTS: In all measurements except for grip strength of the preferred UE, children with USCP were weaker than children with TD. CONCLUSIONS: In children with USCP, muscle strength weakness exists in both UEs. IMPACT: When unimanual or bimanual ability limitations are present in children with unilateral cerebral palsy, investigation of the muscle strength of the nonaffected UE should be part of the assessment.

Relation between grip and pinch strength and pitch type in high school pitchers with and without elbow symptoms.

OBJECTIVE: Gripping and pinching a ball is a fundamentally important part of the kinetic chain for throwing baseball pitches of various types. This study of high school pitchers was conducted to assess the association between grip and pinch strength, the pitch type, and the history of elbow symptoms. METHODS: We examined 133 high school baseball pitchers, all of whom had completed a self-administered questionnaire including items related to pitch type throwing ratios, the age at starting each pitch type, and throwing-related elbow joint pain sustained during the prior 3 years. We measured grip strength and the bilateral side tip, key, and palmar pinch strengths. Comparisons were made between the participants with and without an elbow symptom history to assess the grip and each pinch strength, throwing ratio of pitch type, and the age at starting to throw each pitch type. RESULTS: Pitchers with an elbow symptom history exhibited less difference between the grip strength on the throwing side than those with no elbow symptom history (p = 0.04). No difference was found between participants with and without an elbow symptom history in terms of pinch strength, the throwing ratios of pitch types, or the age at starting to throw pitches of each type. Positive significant association was found between pinch strength on the pitching side and the forkball and screwball throwing ratio (r = 0.27, p = 0.002). CONCLUSION: Grip strength might influence high school baseball pitcher elbow conditions. The frequency of certain pitch types might develop pinch strength in high school baseball pitchers.

Grip force control during object manipulation in cervical myelopathy.

STUDY DESIGN: Cross-sectional research. OBJECTIVES: To objectively evaluate grip force (GF) control while holding a freely movable object in individuals with cervical myelopathy (CM). SETTING: Harunaso Hospital, Takasaki, Japan. METHODS: We studied 52 hands from 26 individuals with CM. Participants performed a grip-and-lift task by pulp pinch using the thumb and index finger before surgery. We monitored individual finger GF (N) during the first 3 s while lifting and holding an object. Correlations between the GF and other clinical tests were evaluated. A multiple stepwise regression analysis was used to examine the contribution of the GF to the severity of clinical symptoms. RESULTS: Thumb GF was negatively correlated with the 10-s test (rs = -0.32), and index finger GF was positively correlated with its cutaneous pressure threshold (rs = 0.34). Multiple regression for the severity of upper extremity symptoms revealed that the model including the GF had a larger adjusted R2 and a lower AIC value than that of conventionally used clinical tests. CONCLUSIONS: These results suggested that the assessment of individual finger GF control could provide an indicator of the clinical severity of upper extremity in individuals with CM.