The contribution of the wrist, elbow and shoulder joints to single-finger tapping.

We aimed to determine the role of the wrist, elbow and shoulder joints to single-finger tapping. Six human subjects tapped with their index finger at a rate of 3 taps/s on a keyswitch across five conditions, one freestyle (FS) and four instructed tapping strategies. The four instructed conditions were to tap on a keyswitch using the finger joint only (FO), the wrist joint only (WO), the elbow joint only (EO), and the shoulder joint only (SO). A single-axis force plate measured the fingertip force. An infra-red active-marker three-dimensional motion analysis system measured the movement of the fingertip, hand, forearm, upper arm and trunk. Inverse dynamics estimated joint torques for the metacarpal-phalangeal (MCP), wrist, elbow, and shoulder joints. For FS tapping 27%, 56%, and 18% of the vertical fingertip movement were a result of flexion of the MCP joint and wrist joint and extension of the elbow joint, respectively. During the FS movements the net joint powers between the MCP, wrist and elbow were positively correlated (correlation coefficients between 0.46 and 0.76) suggesting synergistic efforts. For the instructed tapping strategies (FO, WO, EO, and SO), correlations decreased to values below 0.35 suggesting relatively independent control of the different joints. For FS tapping, the kinematic and kinetic data indicate that the wrist and elbow contribute significantly, working in synergy with the finger joints to create the fingertip tapping task.

[1]  D. Rempel,et al.  VDT-related musculoskeletal symptoms: interactions between work posture and psychosocial work factors. , 1994, American journal of industrial medicine.

[2]  F. Veldpaus,et al.  A least-squares algorithm for the equiform transformation from spatial marker co-ordinates. , 1988, Journal of biomechanics.

[3]  D. Rempel,et al.  A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators , 2006, Occupational and Environmental Medicine.

[4]  W S Marras,et al.  Industrial wrist motions and incidence of hand/wrist cumulative trauma disorders. , 1994, Ergonomics.

[5]  B M Hillberry,et al.  Finger joint force minimization in pianists using optimization techniques. , 1993, Journal of biomechanics.

[6]  Devin L Jindrich,et al.  Finger joint impedance during tapping on a computer keyswitch. , 2004, Journal of biomechanics.

[7]  Nancy A Baker,et al.  Developing an observational instrument to evaluate personal computer keyboarding style. , 2005, Applied ergonomics.

[8]  B Nilsson,et al.  Musculoskeletal disorders among visual display terminal workers: individual, ergonomic, and work organizational factors. , 1995, Ergonomics.

[9]  D. Jindrich,et al.  Finger joint coordination during tapping. , 2006, Journal of biomechanics.

[10]  C. D. Mote,et al.  In vivo finger flexor tendon force while tapping on a keyswitch , 1999, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[11]  F Gerr,et al.  Measurement variability in upper extremity posture among VDT users. , 1997, Applied ergonomics.

[12]  H Kinoshita,et al.  Temporal and force characteristics of fast double-finger, single-finger and hand tapping , 2001, Ergonomics.

[13]  Marras Ws.  Toward an understanding of dynamic variables in ergonomics. , 1992 .

[14]  R H Westgaard,et al.  Motor unit substitution in long-duration contractions of the human trapezius muscle. , 1999, Journal of neurophysiology.

[15]  Mikael Forsman,et al.  Low-threshold motor unit activity during a 1-h static contraction in the trapezius muscle , 2002 .

[16]  Pascarelli Ef,et al.  Soft-tissue injuries related to use of the computer keyboard. A clinical study of 53 severely injured persons. , 1993 .

[17]  B. Visser,et al.  The effect of arm and wrist supports on the load of the upper extremity during VDU work. , 2000, Clinical biomechanics.

[18]  Richard R Neptune,et al.  Biomechanics and muscle coordination of human walking. Part I: introduction to concepts, power transfer, dynamics and simulations. , 2002, Gait & posture.

[19]  E R Serina,et al.  Wrist and forearm postures and motions during typing. , 1999, Ergonomics.

[20]  B. Buchholz,et al.  Anthropometric data for describing the kinematics of the human hand. , 1992, Ergonomics.

[21]  M J Hines,et al.  A dynamic model for finger interphalangeal coordination. , 1988, Journal of biomechanics.

[22]  H M Toussaint,et al.  Segment inertial parameter evaluation in two anthropometric models by application of a dynamic linked segment model. , 1996, Journal of biomechanics.

[23]  Jack Tigh Dennerlein.  Finger flexor tendon forces are a complex function of finger joint motions and fingertip forces. , 2005, Journal of hand therapy : official journal of the American Society of Hand Therapists.

[24]  C D Mote,et al.  A method of measuring fingertip loading during keyboard use. , 1994, Journal of biomechanics.

[25]  D. Kleinbaum,et al.  A prospective study of computer users: I. Study design and incidence of musculoskeletal symptoms and disorders. , 2002, American journal of industrial medicine.

[26]  T J Armstrong,et al.  Hand wrist cumulative trauma disorders in industry. , 1986, British journal of industrial medicine.

[27]  J F Soechting,et al.  Kinematics of typing: parallel control of the two hands. , 1992, Journal of neurophysiology.

[28]  A Leardini,et al.  Position and orientation in space of bones during movement: anatomical frame definition and determination. , 1995, Clinical biomechanics.

[29]  Peter R. Francis,et al.  Differences in the abilities of individual fingers during the performance of fast, repetitive tapping movements , 2003, Experimental Brain Research.

[30]  M. Habal,et al.  Work-related cumulative trauma disorders and interpreters for the deaf. , 2000, Applied occupational and environmental hygiene.

[31]  Thomas Läubli,et al.  Co-activity of the trapezius and upper arm muscles with finger tapping at different rates and trunk postures , 2000, European Journal of Applied Physiology.

[32]  Fredric Gerr,et al.  A prospective study of computer users: II. Postural risk factors for musculoskeletal symptoms and disorders. , 2002, American journal of industrial medicine.

[33]  At L Hof,et al.  Handling of impact forces in inverse dynamics. , 2006, Journal of biomechanics.

[34]  S. Delp,et al.  Variation of muscle moment arms with elbow and forearm position. , 1995, Journal of biomechanics.

[35]  S. Smith,et al.  Hand/Wrist Disorders Among Sign Language Communicators , 2000, American annals of the deaf.

[36]  C. E. Clauser,et al.  Anthropometric Relationships of Body and Body Segment Moments of Inertia , 1980 .

[37]  K Burton,et al.  Biomechanics of human movement: applications in rehabilitation, sports and ergonomics N Berme and A Cappozzo, Eds Bertec Corp., Worthington, Ohio, 1990, 545 pp, $US56.50. [Bertec, 819 Loch Lomond Lane, Worthington, Ohio 43085, USA]. , 1992, Clinical biomechanics.

[38]  Thomas Läubli,et al.  Trapezius Muscle Motor Unit Activity in Symptomatic Participants During Finger Tapping Using Properly and Improperly Adjusted Desks , 2004, Hum. Factors.