The influence of glove and hand position on pressure over the ulnar nerve during cycling

The elastography of distal ulnar nerve branches in cyclists

INTRODUCTION

Forced elbow flexion and pressure during bicycling result in ulnar nerve traction and pressure exerted in Guyon's canal or the nerve's distal branches. The compression of the nerves causes a change in their stiffness related to edema and eventually gradual fibrosis.

PURPOSE

This study aimed to evaluate the elastography of terminal branches of the ulnar nerve in cyclists.

STUDY DESIGN

Cross-sectional study.

METHODS

Thirty cyclists, 32 healthy individuals, and 32 volunteers with ulnar nerve entrapment neuropathies participated in the study. Each participant underwent a nerve examination of the cubital tunnel, Guyon's canal and the deep and superficial branches of the ulnar nerve using shear wave elastography. The cyclist group was tested before and after a 2-hour-long workout.

RESULTS

Before cycling workouts, the ulnar nerve stiffness in the cubital tunnel and Guyon's canal remained below pathological estimates. Cycling workouts altered nerve stiffness in the cubital tunnel only. Notably, the stiffness of the ulnar terminal branches in cyclists was increased even before training. The mean deep branch stiffness was 50.85 ± 7.60 kPa versus 20.43 ± 5.95 kPa (p < 0.001) in the cyclist and healthy groups, respectively, and the mean superficial branch stiffness was 44 ± 12.45 kPa versus 24.55 ± 8.05 kPa (p < 0.001), respectively. Cycling contributed to a further shift in all observed values.

DISCUSSION

These observations indicate the existence of persistent anatomical changes in the distal ulnar branches in resting cyclists that result in increased stiffness of these nerves. The severity of these changes remains, however, to be determined.

CONCLUSIONS

These data show elastography values of the ulnar terminal branches in healthy individuals and cyclists where despite lack of clinical symptoms that they seem to be elevated twice above the healthy range.

Influence of Surface Geometry on Palm and Fist Contact Pressure Distribution During Strikes With the Hand in Automotive Assembly

The increase in repetitive strain injuries to the hand underscores the need for assessing and preventing musculoskeletal overuse associated with hand-intensive tasks. This study investigates the risk of overload injuries in soft tissue structures of the hand by analyzing the pressure distribution and location of peak pressure in the hand during snap-fit connection assembly in the automotive industry. The influence of the surface geometry of automotive trim components the pressure distribution and force imparted during strikes with the palm and the fist are investigated in a cohort of 30 subjects with extensive experience installing trim parts with snap-fit connections. Using the palm or fist (ulnar hand side) of the dominant hand, the subjects struck a simulation device with a flat, rounded, or edged surface geometry. The average peak force applied was 600 N (±122 N), nearly 3 times the force required to overcome the technical resistance of the snap-fit connector (220 N). Fist strikes exerted a 40% higher mean peak pressure and 18% higher mean pressure than did palm strikes. The pressure distribution in the region of the thenar eminence and soft tissue of the ulnar side of the hand did not differ between fist strikes on flat and edged surfaces. Considering the delicate anatomy of the hand, especially the hypothenar muscles on the ulnar side, assembling connection claps using the fist instead of the palm may prevent repetitive blunt trauma to the sensitive blood vessels and nerves in the palm.

The Physiatrist's Guide to Cyclist Palsy: A Narrative Review

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME.

CME OBJECTIVES

At the conclusion of this educational module, participants will be able to: (1) Describe the possible clinical presentations of Cyclist Palsy based on Ulnar nerve anatomy in the wrist and hand; (2) State the cycling-related risk factors for Cyclist Palsy; and (3) Outline the principles in management for Cyclist Palsy.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Preventive strategies, exercises and rehabilitation of hand neuropathy in cyclists: A systematic review

BACKGROUND

Recreation, transportation and sport are the most common uses of bicycles. Unfortunately, repetitive bicycle use can also cause injuries, such as osteoarticular direct and undirect traumatisms and sometimes compression nerve entrapment caused by an extrinsic compressive force.

PURPOSE

The aim of the study is to define diagnostic process, preventive strategies, and treatment of ulnar and median neuropathies in cyclists.

STUDY DESIGN

Systematic review.

METHODS

A search was conducted on PubMed, EMBASE, the Cochrane Library, and Web of Science. Two reviewers independently reviewed articles and came to a consensus about which ones to include. The authors excluded all duplicates, articles involving individuals with other sport-related injuries than cycling, and articles unrelated to peripheral neuropathies. Articles were included if hand palsy was due to peripheral compression of ulnar or median nerve in cyclists.

RESULTS

The search identified 15,371 articles with the keywords "Peripheral Nervous System Diseases" OR "neuropathy" OR "ulnar palsy" OR "median palsy" AND "bicycling" OR "bike" OR "bicycle" OR "cyclist". The reviewers analyzed 48 full texts. There were 20 publications that met the criteria and were included in the systematic review. These articles were used to describe the main methods used for diagnosis, prevention and treatment of hand neuropathy of cyclists.

CONCLUSION

Despite the range of treatment available for peripheral neuropathies, a unique and common protocol is lacking on this specific topic. For this reason, we delineate a definitive recovery protocol to show the best therapeutic methodologies present in the current literature. Preventive strategies, period of rest since the beginning of the symptomatology, rehabilitation training with muscle strengthening, orthoses at night are the first strategies, but if the symptoms persist, pharmacologic treatment and eventual surgical decompression are sometimes the unique solution.

Could Proprioceptive Stimuli Change Saddle Pressure on Male Cyclists during Different Hand Positions? An Exploratory Study of the Effect of the Equistasi® Device

When pedaling, the excessive pressure on the seat has the potential to produce injuries and this can strongly affect sport performance. Recently, a large effort has been dedicated to the reduction of the pressure occurring at the saddle region. Our work aims to verify the possibility of modifying cyclists’ pedaling posture, and consequently the pressure on the saddle, by applying a proprioceptive stimulus. Equistasi® (Equistasi srl, Milano, Italy) is a wearable device that emits focal mechanical vibrations able to transform the body temperature into mechanical vibratory energy via the embedded nanotechnology. The data acquired through a pressure mapping system (GebioMized®) on 70 cyclists, with and without Equistasi®, were analyzed. Pedaling in three positions was recorded on a spin trainer: with hands on the top, hands on the drop handlebar, and hands on the lever. Average force, contact surface, and average and maximum pressure each in different regions of the saddle were analyzed, as well as integral pressure time and center of pressure. In the comparisons between hands positions, overall pressure and force variables were significantly lower in the drop-handlebar position at the rear saddle (p < 0.03) and higher in hand-on-lever and drop-handlebar positions at the front saddle (p < 0.01). When applying the Equistasi device, the contact surface was significantly larger in all hand positions (p < 0.05), suggesting that focal stimulation of the lumbar proprioceptive system can change cyclists’ posture.

Cervical Spine, Upper Extremity Neuropathies, and Overuse Injuries in Cyclists

Upper extremity nerve injuries in cyclists include carpal tunnel syndrome and ulnar neuropathy at the wrist. Electromyography and nerve conduction studies aid in the diagnosis of neuropathies. Diagnostic ultrasonography or MRI can also be helpful for evaluation. Overuse injuries in the upper extremity includes biker's elbow, or a tendinopathy of the common flexor or extensor tendons, which is more common in mountain biking. Neck pain is also a common issue for cyclists. Treatment of these conditions varies from conservative management to surgical options, but a bicycle fit assessment is recommended for any ongoing symptoms.

Biomechanical analysis of force distribution in one-handed and two-handed adult chest compression: a randomised crossover observational study

INTRODUCTION

The standard method of chest compression for adults is a two-handed procedure. One-handed external chest compression (ECC) is used in some situations such as during transport of patients who had an out-of-hospital cardiac arrest, but the quality of one-handed ECC is still not well known. The distribution of force is related to the quality of chest compression and may affect the risk of injury. This study aimed to determine the differences in the quality and potential safety concern between one-handed ECC and two- handed ECC.

METHODS

In this randomised crossover study, participants recruited from National Cheng Kung University Hospital and the ambulance team from the fire bureau were asked to perform one-handed and two-handed ECC on the Resusci Anne manikin according to standard 2015 ECC guidelines. The MatScan Pressure Measurement system was used to investigate the compression pressure and force distribution.

RESULTS

Two-handed ECC had better results than one-handed ECC in terms of the median (IQR) depth (51.00 (41.50-54.75) mm vs 42.00 (27.00-49.00) mm, p=0.018), the proportion of depth accuracy (82.05% (13.95%-99.86%) vs 11.17% (0.00%-42.13%), p=0.028) and the proportion of incomplete recoil (0.23% (0.01%-0.44%) vs 2.42% (0.60%-4.21%), p=0.002). The maximum force (45.72 (36.10-80.84) kgf vs 35.64 (24.13-74.34) kgf, p<0.001) and ulnar-radial force difference (7.13 (-16.58 to 21.07) kgf vs 23.93 (11.19-38.74) kgf, p<0.001) showed statistically significant differences. The perceived fatigue of two-handed ECC versus one-handed ECC was 5.00 (3.00-6.00) vs 6.00 (5.00-8.00), p<0.001.

CONCLUSION

The quality of one-handed ECC, based on depth and recoil, is worse than that of standard two-handed ECC. The pressure and force distribution of one-handed ECC result in greater ulnar pronation of the hand than that of two-handed ECC. One-handed ECC more easily causes operator fatigue. Acknowledging these findings and adjusting training for one-handed ECC would potentially improve the quality of cardiopulmonary resuscitation during transport.

Design of an ergonomic gestural interface for professional road cycling

BACKGROUND

Connected bike computers can support professional cyclists in achieving better performances but interacting with them requires taking their hands off the handlebar compromising focus and safety.

OBJECTIVE

This research aims at exploring the design of an ergonomic interface based on micro-gestures that can allow cyclists to interact with a device while holding the handlebar.

METHODS

Three different studies were conducted with seven professional cyclists adopting the gesture-elicitation technique. One study aimed at eliciting free micro-gestures; a second to evaluate gestures recognizable with a smart glove; the last focused on the gestures recognized through an interactive armband.

RESULTS

The analysis of the micro-gestures elicited during these studies allowed producing a first set of guidelines to design gestural interfaces for drop-bars (a specific type of handlebar for road bikes). These guidelines suggest which fingers to use and how to design their movement in order to provide an ergonomic interface. It also introduces the principle of symmetry for the attribution of symbols to symmetric referents. Finally, it provides suggestions on the design of the interactive drop-bar.

CONCLUSIONS

The guidelines provided in this paper can support the design of gestural interfaces for professional cyclists that can enhance performance and increase safety.

[Current trends and injuries in cycling: faster, further, e-bike?]

During the past decade, technical innovations (e.g., carbon as a new material, disk brakes, hydraulic shock absorbers, electric transmissions) and lifestyle changes have significantly influenced recreational and professional cycling. In contrast to the past, where ambitious leisure cyclists were primarily interested in the recreational value of nature and landscape, cyclists of all ages are nowadays increasingly focused on performance and self-optimization. Simultaneously, manufacturers have adapted to differing customer requirements: besides the traditional extremities of road and mountain bikes, many specialized models have been designed for special applications: trekking, cyclocross, gravel, full-suspension, single-track, hardtail, downhill, fatbike, etc. For biking fans who are no longer able to meet their own demands due to individual physical restrictions or defined health problems, electric-assist bikes (pedelecs or "e-bikes") were recently introduced. While these are becoming increasingly popular, they have also increased the number of accidents and injuries. The current work provides an update on relevant sport medical and orthopaedic challenges brought on by these developments in cycling.

POSTURAL COMPARISON BETWEEN A CONVENTIONAL BICYCLE HANDLEBAR AND AN ELLIPTICAL HANDLEBAR

ABSTRACT Introduction Cycling has been encouraged, not only as a way to reduce environmental pollution but also to improve people’s health. For many, the bicycle is their sole form of transportation. In view of this growth, and potential risk of injury due to excessive bicycle use, an elliptical handlebar was developed with the purpose of modifying the hand and forearm grip and improving the rider’s posture. Objective To compare vertebral spine angulations with the use of conventional and elliptical handlebars. Methods Twenty-six individuals participated in this study, in which they pedaled for two minutes with elliptical handlebars and two minutes with conventional handlebars, in order to compare the angulation of the vertebral spine using each type of handlebars. The images were filmed and evaluated by the Kinovea kinematic evaluation program. The statistical analysis was performed by Graphpad Prism 7. Results It was observed that 88% of the participants had a more upright vertebral spine angulation when using the elliptical handlebar, with statistically significant difference (p = 0.0001). Conclusion Bearing in mind that the handlebars were placed in similar support positions, it was observed, based on the quantified data, that the posture is more upright, and therefore more suitable, when using the elliptical handlebars. Level of Evidence II; Diagnostic Studies - Investigating a Diagnostic Test.

Changes in the pressure distribution by wrist angle and hand position in a wrist splint

The study was conducted to provide basic data to develop a system that distributes pressure over a broader area by measuring and analyzing pressures in various wrist angles and hand positions while wearing a wrist splint. With 0, 15, 30, and 45 degrees of wrist extension, full-finger extension and finger flexion, pressure distribution changes were measured three times. Average peak pressure was analyzed and mean value picture (MVP) in zones 3-5 was calculated. A one-way Anova was conducted to identify changes in pressure distribution by wrist angle and hand position. Mean peak pressure values (kPa) in zones 3-5 changed depending on the wrist angle. Peak pressures (kPa) changed significantly in 15, 30, and 45 degrees wrist extension, depending on the hand position. Since pressure distributions differ depending the wrist angle and hand position (finger flexion), it is necessary to consider how pressure varies in each wrist position and to provide information on postures that should be avoided during tasks and occupational activities based on various wrist angles or hand positions.

Structural and functional anatomy of the palmaris brevis: grasping for answers

The palmaris brevis (PB) is a small cutaneous hand muscle that has been described as the most mysterious muscle from a functional and developmental perspective [Kaplan () Kaplan's Functional and Surgical Anatomy of the Hand]. Functionally, the PB is considered to deepen the hollow of the palm and to protect the neurovasculature of the ulnar canal. Although the function of the PB has been inferred from cadaveric observations, the electromyographic (EMG) activity of this muscle has not been explored systematically during specific movements of the hand. The purpose of this study was to record PB intramuscular EMG activity during dynamic grasping tasks, and to quantify the change in PB muscle length (M_L ) and thickness (M_T ) incurred during maximal contraction using ultrasound imaging. Intramuscular EMG was recorded from the PB in the dominant hands of 12 healthy participants (11 males, one female; age: 27 ± 4 years) during maximal abduction, flexion and opposition of the 5th digit, and two grasping tasks. Abduction of the 5th digit yielded the greatest EMG activity in most individuals (seven out of 11), and produced significantly less PB EMG activity when compared with grasping a cylindrical-shaped object (P = 0.003) but not a spherical-shaped object (P = 0.130). During maximal abduction of the 5th digit, PB M_L decreased in both the left (28 ± 11%; P = 0.002) and right (32 ± 5%; P = 0.002) hands. Similarly, a concomitant increase in PB M_T was observed in the left (68 ± 30%; P = 0.002) and right (85 ± 44%; P = 0.002) hands during the same contraction. These EMG results indicate that the PB is voluntarily activated during prehensile and non-prehensile movements of the hand with significant changes in muscle architecture. The study supports the preservation of the PB in surgical procedures based on its proposed protective role as a muscular barrier to the neurovasculature within the ulnar canal.

Ulnar Neuropathy in Cyclists

The form and function of the cyclist exposes the ulnar nerve to both traction and compressive forces at both the elbow and wrist. Prevention of ulnar neuropathy and treatment of early symptoms include bike fitting, avoidance of excessive or prolonged weight-bearing through the hands, and the use of padded gloves. For persisting or progressive symptoms, a thorough history and physical examination is essential to confirm the diagnosis and to rule out other sites of nerve compression. The majority of compression neuropathies in cyclists resolve after appropriate rest and conservative treatment; however, should symptoms persist, nerve decompression may be indicated.

The force output of handle and pedal in different bicycle-riding postures

The purpose of this study was to analyse the force output of handle and pedal as well as the electromyography (EMG) of lower extremity in different cycling postures. Bilateral pedalling asymmetry indices of force and EMG were also determined in this study. Twelve healthy cyclists were recruited for this study and tested for force output and EMG during steady state cycling adopting different pedalling and handle bar postures. The standing posture increased the maximal stepping torque (posture 1: 204.2 ± 47.0 Nm; posture 2: 212.5 ± 46.1 Nm; posture 3: 561.5 ± 143.0 Nm; posture 4: 585.5 ± 139.1 Nm), stepping work (posture 1: 655.2 ± 134.6 Nm; posture 2: 673.2 ± 116.3 Nm; posture 3: 1852.3 ± 394.4 Nm; posture 4: 1911.3 ± 432.9 Nm), and handle force (posture 1: 16.6 ± 3.6 N; posture 2: 16.4 ± 3.6 N; posture 3: 26.5 ± 8.2 N; posture 4: 41.4 ± 11.1 N), as well as muscle activation (posture 1: 13.6-25.1%; posture 2: 13.0-23.9%; posture 3: 23.6-61.8%; posture 4: 22.5-65.8%) in the erector spine, rectus femoris, tibialis anterior, and soleus. However, neither a sitting nor a standing riding posture affected the hamstring. The riding asymmetry was detected between the right and left legs only in sitting conditions. When a cyclist changes posture from sitting to standing, the upper and lower extremities are forced to produce more force output because of the shift in body weight. These findings suggest that cyclists can switch between sitting and standing postures during competition to increase cycling efficiency in different situations. Furthermore, coaches and trainers can modify sitting and standing durations to moderate cycling intensity, without concerning unbalanced muscle development.

Analysis of the position of the branches of the ulnar nerve in Guyon's canal using high-resolution MRI in positions adopted by cyclists

PURPOSE

To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon's canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists.

MATERIALS AND METHODS

Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH.

RESULTS

The mean distances between the SB (d s) and DP (d p) and HH were 2.4 and 0.6 mm, respectively. The d s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it.

CONCLUSION

This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon's canal syndrome in cyclists.

Biomechanical Comparison of Shorts With Different Pads: An Insight into the Perineum Protection Issue

An intensive use of the bicycle may increase the risk of erectile dysfunction and the compression of the perineal area has been showed to be a major mechanism leading to sexual alterations compromising the quality of life. Manufacturers claim that pads contribute to increase cyclists perineal protection ensuring a high level of comfort. To investigate the influence of various cycling pads with regard to perineal protection and level of comfort. Nine club road cyclists rode 20 min on a drum simulator, located at the Nutrition and Exercise Physiology Laboratory, at a constant speed and gear ratio wearing the shorts with 3 cycling pads of different design and thickness: basic (BAS), intermediate (INT), and endurance (END). Kinematics and pressure data were recorded at min 5, 15, and 20 of the test using a motion capture system and a pressure sensor mat. The variables of interest were: 3-dimensional pelvis excursions, peak pressure, mean pressure, and vertical force. The comfort level was assessed with a ranking order based on the subjects' perception after the 20-min trials and measuring the vertical ground reaction force under the anterior wheel as well as the length of the center of pressure (COP) trajectory on the saddle. Results showed that the vertical force and the average value of mean pressure on the saddle significantly decreased during the 20-min period of testing for BAS and END. Mean peak pressure on the corresponding perineal cyclist area significantly increased only for BAS during the 20-min period. Interestingly objective comfort indexes measured did not match cyclists subjective comfort evaluation. The lower capacity of BAS to reduce the peak pressure on the corresponding perineal area after 20 min of testing, together with its positive comfort evaluation, suggest that a balance between protection and perceived comfort should be taken into account in the choice of the pad. Hence, the quantitative approach of objective comfort indexes introduced in this study could be helpful for manufacturers in the development of their protective pads.