Handle Size Research Articles

Effect of laparoscopic handle size on surgical performance: A randomized crossover trial

Laparoscopic instrument handles design and dimensions are crucial to determine the configuration of surgeons' hand grip and, therefore, can have a deleterious effect on overall surgical efficiency and surgeons' comfort. The aim of this study is to investigate the impact of laparoscopic handle size and hand surface area on surgical task performance. A single-blind, randomized crossover trial was carried out with 29 novice medical students. Participants performed three simulated tasks in "black box" simulators using two scissor-type handles of different sizes. Surgical performance was assessed by the number of errors and time required to complete each task. Hand anthropometric data were measured using a 3D scanner. Execution time was significantly higher when cutting and suturing tasks were performed with the smaller handle. In addition, hand surface area was positively correlated with peg transfer task time when performed with the standard handle and was correlated with cutting task time in small and standard handle groups. We also found positive correlations between execution time and the number of errors executed by larger-handed participants. Our findings indicate that laparoscopic handle size and hand area influence surgical performance, highlighting the importance of considering hand anthropometry variances in surgical instrument design.

A new species of Versteria (Cestoda: Taeniidae) parasitizing Neogale vison and Lontra canadensis (Carnivora: Mustelidae) from Western Canada.

Via molecular and morphological analyses, we describe adult specimens of a new species of Versteria (Cestoda: Taeniidae) infecting mink and river otter (Carnivora: Mustelidae) in Western Canada, as well as larval forms from muskrat and mink. These sequences closely matched those reported from adult specimens from Colorado and Oregon, as well as larval infections in humans and a captive orangutan. We describe here a new species from British Columbia and Alberta (Canada), Versteria rafei n. sp., based upon morphological diagnostic characteristics and genetic distance and phylogeny. Versteria rafei n. sp. differs from the three other described species of the genus in the smaller scolex and cirrus sac. It also differs from V. mustelae (Eurasia) and V. cuja (South America) by having an armed cirrus, which is covered in hair-like bristles, and in the shape of its hooks, with a long thorn-like blade, and short or long handle (vs. a short sharply curved blade and no difference in handle size in previously described species). The poorly known V. brachyacantha (Central Africa) also has an armed cirrus and similarly shaped hooks. However, it differs from the new species in the number and size of hooks. Phylogenetic analysis of the cox1 and nad1 mitochondrial regions showed that our specimens clustered with isolates from undescribed adults and larval infections in North America, and separate from V. cuja, confirming them to be a distinct species from the American Clade.

Gender equity in surgical instruments: ergonomics of ring-handled forceps

Introduction Female surgeons have ergonomic issues with commercialized instruments tailored for male surgeons. The purpose of this study was to identify satisfaction levels and ergonomic problems of female surgeons while using laparoscopic forceps with ring-handles and suggest improvement measures. Material and methods A questionnaire was sent to 19,405 members of the Japanese Society of Gastroenterological Surgery via email between 1 August 2022 and 30 September 2022. It included demographic information and specific questions regarding the use of laparoscopic forceps with ring- handles (ergonomic evaluation, influence of the negative aspects of laparoscopic forceps during surgery, physical discomfort in the hands and fingers, degree of satisfaction, and handle size). Results Valid responses were received from 1,030 respondents (131 female and 899 male surgeons). The ergonomics of the laparoscopic forceps with ring-handles were rated lower by female surgeons in all ten categories (all p value < 0.05). They also reported a negative impact on surgical manipulation and discomfort to their hands and fingers. Conclusions Female surgeons had a wide variety of ergonomic problems when using laparoscopic forceps with ring-handles, and showed lower levels of satisfaction. Developing a different model tailored to female surgeons with smaller hands and a weaker grip could be a viable solution.

Variables affecting surgeons' use of, and preferences for, instrumentation in veterinary laparoscopy.

To investigate the impact of variables on use and preference of common laparoscopic instruments. Online survey. Surgeons (n = 140) with 3 years or more laparoscopic experience. Electronic survey distributed via specialty group LISTSERVEs and Facebook groups. Responses collected included surgeon attributes, preferences, and surgical practice data. Statistical analysis was performed using Fishers exact, ANOVA, Tukey Kramer honestly significant difference (HSD) test, linear regression, and logistic regression. Ninety-eight of 140 respondents answered instrument-related questions and the completion rate of these questions was 76%: 48% of females and 49% of males responded to the survey. The median glove size of respondents was size 7 (range, 5.5 to 8.5). Closing laparoscopic Babcock forceps (p = .018), rotating cup biopsy forceps (p = .003), and manipulating endoscopic staplers (p < .001) were more difficult for surgeons with smaller glove sizes. The median difficulty score for the endoscopic stapler was 4/10 and the median percentage of time this was found difficult was 25%. Reusable instruments were preferred over disposable single-use instruments. The pistol grip was preferred for grasping and retracting (54/98, 55%) and fine dissection (46/96, 48%), while the axial grip was preferred for suturing and knot tying (61/98, 62%). Surgeons with smaller glove sizes (<6.5) experience more difficulty when using common laparoscopic instruments. The endoscopic stapler was the most difficult to use. When purchasing laparoscopic instrumentation, surgeons should review all available options in handle size and design to improve ergonomics during minimally invasive procedures.

Helping Surgeons’ Hands: A Biomechanical Evaluation of Ergonomic Instruments

"Ergonomic" is a common descriptor for a desk or computer workspace but is a term rarely used to describe a surgical instrument. Instead, surgeons spend many hours in inconvenient positions, often using instruments that are not ergonomic. Improving the ergonomics of surgical instruments may decrease the required force for simple tasks and allow for more efficient surgery. To evaluate the impact of ergonomic surgical instruments, the authors developed ergonomic screwdriver handles. The shape and size of these handles were engineered using previous dental studies and 3-dimensional modeling to create an ideal handle for specific glove sizes. Participants were recruited to test 3 different ergonomic handle sizes against a standard screwdriver while assessing digital peak force, digital contact area, and participant preference. Ten participants (3 women) with glove sizes ranging from 6 to 8 were evaluated. Ergonomic screwdriver handles sized for glove sizes 6 and 7 required significantly less thumb peak force than the standard screwdriver for all participants (702 N for glove size 6 and 567 N for glove size 7 ergonomic screwdrivers, vs 1780 N for "one size fits all" standard screwdriver). Participants consistently preferred screwdrivers that required lower thumb and index finger forces. All ergonomic handles required lower thumb and index finger force. Eighty percent of participants preferred a screwdriver modeled within 1 glove size of their own. Improved ergonomic handles require less force and are preferred by surgeons. The significant decrease in thumb peak force for glove sizes 6 and 7 suggests that there is room for ergonomic improvement in instruments, especially for surgeons with smaller hands. Manufacturing ergonomic screwdriver handles and using the evolving convenience of 3-dimensional printing may help to develop a more comfortable work environment for surgeons.

Single Use or Disposable Flexible Bronchoscopes: Bench Top and Preclinical Comparison of Currently Available Devices.

Data regarding the risk of infection related to reusable bronchoscopes, the global drive toward disposable technology and the COVID-19 pandemic have led to an increase in the use and production of single use or disposable bronchoscopes. An in-depth comparison of all available devices has not been published. A benchtop comparison of the Ambu®aScopeTM, Boston Scientific® EXALTTM Model B, the Surgical Company Broncoflex© Vortex, Pentax® Medical ONE Pulmo™, and Vathin® H-SteriscopeTM (all 2.8 mm inner dimension other than the Pentax single-use flexible bronchoscope (3 mm)) was undertaken including measurement of maximal flexion and extension angles, thumb force required and suction with and without biopsy forceps. Thereafter, preclinical assessment was performed with data collected including experience, gender, hand size, and scope preference. The Vathin single-use flexible bronchoscope had the biggest range of tip movement from flexion to extension with and without forceps. The Boston single-use flexible bronchoscope required the maximal thumb force but had the least reduction of tip movement with forceps. The Boston single-use flexible bronchoscope significantly outperformed all other scopes including the standard Pentax scope and was the only scope capable of suctioning pseudo-mucus around the forceps. Although there was no significant difference in preference in the overall group, females and those with smaller hand size preferred the Pentax and males the Broncoflex single-use flexible bronchoscope. Currently available single-use flexible bronchoscopes differ in several factors other than scope sizes and monitor including suction, turning envelope, and handle size. Performance in the clinical setting will be key to their success.

Influence of Product Interface Material Stiffness on Human Tactile Perception during a Grasping Task

When considering product handle ergonomics, authors have focused on product handle sizes and shapes, while handle materials have been largely ignored. Authors have shown that handles coated with rubber foam were more comfortable than stiff handles. However, they did not provide detailed material properties, nor did they investigate different stiffnesses and their impact on tactile perception during grasping. Therefore, in this article, we investigated the influence of product interface material stiffness using a common wood sawing task with a saw handle made of hard plastic and 3D-printed deformable material with different stiffnesses. The results showed that user tactile perception can be improved significantly where the 3D-printed cellular density, and, hence material stiffness, has a significant influence on the resulting tactile perception. However, results have shown that the material stiffness must be determined appropriately to maintain the stability of the products in hands. The results also suggest that the product interface material had a greater influence on the reported overall comfort rating than the product handle shape in the sawing task.

Anthropometrics Impact Army Combat Fitness Test Performance in Reserve Officer Training Corps Cadets.

Fitness is a vital component in military success. The Army is in the process of implementing a new assessment for soldier fitness, the Army Combat Fitness Test (ACFT). Success on the assessment is a major factor in job assignments and promotional opportunities. This generates questions related to modifiable (i.e., fitness and body composition) and non-modifiable (i.e., limb length and testing equipment) factors impacting performance. Currently, anthropometrics differences in ACFT performance have not been investigated. Thus, this study aimed to assess the impact of anthropometrics on ACFT performance in Reserve Officer Training Corps Cadets. Anthropometric measures and ACFT scores were collected from Reserve Officer Training Corps cadets (n = 105, age: 20.4 ± 2.4 years, body mass index: 25.0 ± 2.8 kg/m2, and M/F = 84/21). All ACFT events were evaluated by certified graders. Measurement locations were based on established anthropometric assessment standards and previous research (hand, lower arm, upper arm, upper leg, lower leg, and torso lengths). The study was approved by the Auburn University Institutional Review Board (protocol code #21-410). There were weak correlations between hand length and three-repetition maximum deadlift [0.393; P ≤ .001], standing power throw [0.399; P ≤ .001], sprint-drag-carry [-0.315; P = .002], and ACFT score [0.212; P = .035]. The lower leg had weak correlations with standing power throw [0.249; P = .013], sprint-drag-carry [-0.215; P = .033], and ACFT score [0.213; P = .034]. Hand and lower leg length impacted individual event performances when comparing shortest and longest limb lengths [all P values <.05]. Hand and lower leg length significantly impact ACFT performance. These results present practical information to individuals responsible for developing protocols and scoring for the ACFT. Reassessment of events and the equipment utilized are warranted to assure that event performance is not hindered by a non-modifiable factor that is not representative of fitness or occupational demands. Future work should investigate how different trap-bar and kettlebell handle sizes, as well as medicine ball sizes, impact performance on the ACFT.

3D printed deformable product handle material for improved ergonomics

In product handle ergonomic design optimisation researchers focused mainly on the size and shape of the handles; however, interface handle materials have been neglected despite showing potential to improve ergonomics. Deformable elastic cellular meta-materials with pre-engineered mechanical response based on the biomechanical evaluation of human hand soft tissue during grasping were designed and manufactured using commercial 3D printing technology. A sawing task has been utilized for the evaluation of subjective comfort rating. Based on distinct mechanical behaviour of cellular solids, 3D printed handle interface material stays stiff at the low grasping forces and deforms only when certain amount of contact pressure is reached. Cellular density can be easily adjusted to meet the desired biomechanical response. Hereby stability of the handle in hands is maximised while providing more uniform contact pressure distribution on the soft tissue at higher grasping forces. By this means comfort rating is also increased compared to stiff handle interface materials such as plastic. Results also suggest the handle material has greater influence on the comfort rating than the handle size and shape. Relevance to industryApplication of this research includes the utilization of this methodology and design techniques in development of handles for powered and non-powered tools and handheld products for improved comfort and also ergonomics.

Hand tool handle size and shape determination based on hand measurements using a contour gauge

AbstractThe purpose of this study is to provide a novel approach to tool handle design and development based on measurements of hand shape using a contour gauge. In general, traditional design techniques, designing based on anthropometric data, and derived mathematical models do not incorporate enough subject data to design a customized product. First, anthropometric measurements on the right hand of 60 participants were collected with a contour gauge to manufacture matching handles. A curved handle fitting the human hand was constructed with common computer‐aided design software, and cylindrical handles and elliptical handles were added for comparison. All of the handles were used to record the participants' grip force to evaluate the operating efficiency of the handles. Finally, the participants completed a comfort‐rating questionnaire. The results show that contours based on the hand provided the highest operating performance and the best overall comfort‐rating compared to cylindrical handles and elliptical cylindrical handles. The newly developed handles in the grip force tasks have the highest push performance and the best comfort ratings compared to traditional cylindrical and elliptical handles. The developed handles could provide the hand tool industry information on developing and manufacturing many other similar handle designs (such as those for saws and electric screwdrivers).

Comparative Study of the Use of Different Sizes of an Ergonomic Instrument Handle for Laparoscopic Surgery

Previous studies have shown that the handle design of laparoscopic instruments is crucial to surgical performance and surgeon’s ergonomics. In this study, four different sizes of an ergonomic laparoscopic handle design were tested in a blind and randomized fashion with twelve surgeons. They performed three laparoscopic tasks in order to analyze the influence of handle size. Execution time, wrist posture, and finger and palm pressure were evaluated during the performance of each task. The results show a significant reduction in the time required to complete the eye-manual coordination task using the appropriate handle. The incorrectly sized handle resulted in a rise in palm pressure and a reduction in the force exerted by the thumb during the transfer task. In the hand-eye coordination task, the use of the right handle size led to an increase in middle finger pressure. In general, surgeons had an ergonomically adequate wrist flexion in all tasks and an acceptable radio-ulnar deviation during the transfer task using the ergonomic instrument handle. Surgeons found it comfortable the use of the ergonomic handle. Therefore, the use of an appropriately sized instrument handle allows surgeons to improve ergonomics and surgical performance during the laparoscopic practice.

The Influence of Hand Tool Design on Hand Grip Strength: A Review

Hand is made up of bones, tendons, ligaments, nerves and blood vessels that can be easily debilitated and injured if the hand tool is not design ergonomically. Recently researchers have examined the effects of individual, environmental and occupational factors on hand grip strength. However, information on the influence of hand tool design on hand grip strength is still lacking. The aim of this paper is to provide a comprehensive review of factors influencing hand grip strength focusing more towards hand tool design factors. The authors searched the journal articles, book and guidelines from the online databases of Google Scholar, ScienceDirect and Pubmed. Fourteen factors of hand tools design were found to have significant effect on the hand grip strength. The handle size shows the most significant factor for hand grip strength.

Accuracy Constraints Improve Symmetric Bimanual Coordination for Children with and without Unilateral Cerebral Palsy

ABSTRACTPurpose: To evaluate the influence of accuracy constraints on functional symmetric bimanual coordination for children with Unilateral Spastic Cerebral Palsy (USCP). Methods: Ten children with USCP (average age: 9.6; MACS levels: I–II), ten typically developing children, and ten adults lifted a tray with a water bottle on top. Two accuracy constraints of handle size and cap condition were manipulated. Results: Children with USCP exhibited greater bilateral asymmetry in hand vertical position, timing, upper arm, and elbow control than other groups. Smaller handle decreased bilateral timing differences at lift onset and offset, and decreased bilateral elbow asymmetry at reach and lift offset. Without a cap (accuracy constraint), they showed greater trunk involvement, and less bilateral vertical position and lift offset timing differences (all p < .05). Conclusions: Children with USCP showed impaired symmetric bimanual coordination. Higher accuracy constraints improved some bimanual spatial and temporal control. Therefore, task accuracy constraints should be manipulated carefully for training.

Preliminarily study on the maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on gastropods

The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four gastropods species (Bellamya aeruginosa, Radix auricularia, Parafossarulus sinensis and Alocinma longicornis) under laboratory conditions. In the maximum handling size trial, five fish from each age group (1-year-old and 2-year-old) and each genotype (transgenic and non-transgenic) of common carp were individually allowed to feed on B. aeruginosa with wide shell height range. The results showed that maximum handling size increased linearly with fish length, and there was no significant difference in maximum handling size between the two genotypes. In the size selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on three size groups of B. aeruginosa. The results show that the two genotypes of C. carpio favored the small-sized group over the large-sized group. In the species selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on thin-shelled B. aeruginosa and thick-shelled R. auricularia, and five pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on two gastropods species (P. sinensis and A. longicornis) with similar size and shell strength. The results showed that both genotypes preferred thin-shelled Radix auricularia rather than thick-shelled B. aeruginosa, but there were no significant difference in selectivity between the two genotypes when fed on P. sinensis and A. longicornis. The present study indicates that transgenic and non-transgenic C. carpio show similar selectivity of predation on the size- and species-limited gastropods. While this information may be useful for assessing the environmental risk of transgenic carp, it does not necessarily demonstrate that transgenic common carp might have lesser environmental impacts than non-transgenic carp.

Habitat augmentation drives secondary invasion: an experimental approach to determine the mechanism of invasion success.

The entry of secondary invaders into, or their expansion within, native communities is contingent on the changes wrought by other (primary) invaders. When primary invaders have altered more than one property of the recipient community, standard descriptive and modeling approaches only provide a best guess of the mechanism permitting the secondary invasion. In rainforest on Christmas Island, we conducted a manipulative field experiment to determine the mechanism of invasion success for a community of land snails dominated by non-native species. The invasion of rainforest by the yellow crazy ant (Anoplolepis gracilipes) has facilitated these land snails, either by creating enemy-free space and/or increased habitat and resources (in the form of leaf litter) through the removal of the native omnivorous-detritivorous red land crab (Gecarcoidea natalis). We manipulated predator densities (high and low) and leaf litter (high and low) in replicated blocks of four treatment combinations at two sites. Over the course of one wet season (fivemonths), we found that plots with high leaf litter biomass contained significantly more snails than those with low biomass, regardless of whether those plots had high or low predation pressure, at both the site where land crabs have always been abundant, and at the site where they have been absent for many years prior to the experiment. Each site was dominated by small snail species (<2mm length), and through handling size and predation experiments we demonstrated that red crabs tend not to handle and eat snails of that size. These results suggest that secondary invasion by this community of non-native land snails is facilitated most strongly by habitat and resource augmentation, an indirect consequence of red land crab removal, and that the creation of enemy-free space is not important. By using a full-factorial experimental approach, we have confidently determined-rather than inferred-the mechanism by which primary invaders indirectly facilitate a community of secondary invaders.

Effectiveness of adaptive silverware on range of motion of the hand.

Background. Hand function is essential to a person’s self-efficacy and greatly affects quality of life. Adapted utensils with handles of increased diameters have historically been used to assist individuals with arthritis or other hand disabilities for feeding, and other related activities of daily living. To date, minimal research has examined the biomechanical effects of modified handles, or quantified the differences in ranges of motion (ROM) when using a standard versus a modified handle. The aim of this study was to quantify the ranges of motion (ROM) required for a healthy hand to use different adaptive spoons with electrogoniometry for the purpose of understanding the physiologic advantages that adapted spoons may provide patients with limited ROM.Methods. Hand measurements included the distal interphalangeal joint (DIP), proximal interphalangeal joint (PIP), and metacarpophalangeal joint (MCP) for each finger and the interphalangeal (IP) and MCP joint for the thumb. Participants were 34 females age 18–30 (mean age 20.38 ± 1.67) with no previous hand injuries or abnormalities. Participants grasped spoons with standard handles, and spoons with handle diameters of 3.18 cm (1.25 inch), and 4.45 cm (1.75 inch). ROM measurements were obtained with an electrogoniometer to record the angle at each joint for each of the spoon handle sizes.Results. A 3 × 3 × 4 repeated measures ANOVA (Spoon handle size by Joint by Finger) found main effects on ROM of Joint (F(2, 33) = 318.68, Partial η2 = .95, p < .001), Spoon handle size (F(2, 33) = 598.73, Partial η2 = .97, p < .001), and Finger (F(3, 32) = 163.83, Partial η2 = .94, p < .001). As the spoon handle diameter size increased, the range of motion utilized to grasp the spoon handle decreased in all joints and all fingers (p < 0.01).Discussion. This study confirms the hypothesis that less range of motion is required to grip utensils with larger diameter handles, which in turn may reduce challenges for patients with limited ROM of the hand.

Optimisation of a laparoscopic tool handle dimension based on ergonomic analysis

The techniques of Minimally Invasive Surgery (MIS) have quickly entered everyday surgical practice, and are steadily displacing traditional procedures. The reason is the advantages they have for the patient, both during surgery and in postoperative recovery. However, poor ergonomic design of the instruments used in MIS causes surgeons muscle fatigue and injuries (such as paraesthesia, etc.), forcing them to refrain from performing operations for several days or even weeks, which supposes costly losses of time and money.The objective of the present study was to optimize the handle size of a laparoscopic grasper tool. The study was conducted with the participation of 135 surgeons. Each participant performed a series of trials in which they executed the same action several times with the same tool (same in terms of the geometrical form of the handle) but of different dimensions (size) in order to determine the optimal diameter. The results were then subjected to a statistical analysis to study the relationship between the size of the surgeon's hand and the perceived optimal diameter of the handle from an ergonomic point of view.There stands out among the conclusions drawn from the study that there is indeed a relationship between the size of a surgeon's hand and the optimal handle size for them to use in surgery. In this sense, one of the most relevant results is that it is necessary to consider four different handle sizes groups (XS, S, M and L) instead of the three groups proposed by Greiner (1991). Another interesting result is that all surgeons in the smallest handle size group (XS) were women, and in the L group were men. Also it was interesting to note that, for the intermediate hand sizes (S and M), the sex of the surgeon conditioned the optimal handle size, and that the surgeon's experience and surgeon's handedness were not factors affecting the optimal diameter of the handle. Relevance to industryThe results of this work can assist designers of grasping tools in developing better handles and provide required sizing for improved comfort, performance and lowering the risk of cumulative traumatic disorders. It is important to note that it is not necessary to design the handle of the grasper tool for each surgeon hand, but also with four hand size categories is possible to offer an appropriate handle size for all surgeons independently of their hand sizes.

Multiaxis grip characteristics for varying handle diameters and effort.

A multiaxis dynamometer was used to quantify grip force vector angles and longitudinal centers of pressure (COPs) while varying handle size and effort used. Authors of many studies have examined maximum grip strength using scalar instruments; a few have measured two-axis forces limited to one or more finger contact. This novel dynamometer uses two instrumented beams that are grasped by the distal fingers and proximal palm to compute two orthogonal components of force and the longitudinal COP through which the force acts. Sixteen healthy, right-handed participants grasped the multiaxis dynamometer with plastic handles ranging in diameter from 3.81 to 7.62 cm. They were required to scale their effort to 25%, 50%, 75%, and 100% of maximum. Grip force vector angles were affected by both handle diameter and effort level, with angles increasing an average of 8.1° from the least to greatest effort. Longitudinal COP, averaged among the two beams, shifted 1.75 cm radially as handle diameter increased from 3.81 cm to 7.62 cm. Average COP along the beam in contact with the distal finger segments shifted 0.75 cm ulnarly as effort level increased from 25% to 100% of maximum. Grip force characteristics changed with handle diameter and effort level. Overall grip force magnitude comprised both force components measured. Understanding grip characteristics should be important for handle and grip design and for evaluating hand function.

Potential effects of racket grip size on lateral epicondilalgy risks

The effects of tennis racket grip size on the forces exerted by muscles affecting lateral epicondylalgia (LE) were assessed in this study. Grip forces and joint moments applied on the wrist were quantified under three different handle size conditions, with and without induced muscle fatigue for intermediate and advanced players. The obtained experimental results were then used as input data of a biomechanical model of the hand. This simulation aimed to quantify the impact of grip strength modulation obtained in the experiment on the wrist extensor muscle forces. Our results show that there is an optimal grip diameter size defined as the handle inducing a reduced grip force during the stroke, in both fatigued and non-fatigued sessions. The results of the simulation suggested that extensor muscles were highly employed during forehand strokes, which confirms that the mechanical overuse of extensor tendons is a potential risk factor for tennis elbow occurrence. The handle grip size appeared to be a significant factor to reduce this extensor tendon loading. This suggests that grip size should be taken into account by players and designers in order to reduce the mechanical risk factors of overuse injury occurrence.

2D1-1 松葉杖のグリップ径が杖使用時における手部の負担に及ぼす影響

2D1-1 松葉杖のグリップ径が杖使用時における手部の負担に及ぼす影響