Finger and Hand Extension & Abduction Reference Values
A clinician quick-reference for interpreting Splayometer measurements while device-specific norms are in development.
Scope of available data
Published norms exist for grip and pinch (Mathiowetz 1985). Finger extension and abduction data is more limited and largely from biomechanics research, not clinical norming. Splayometer-specific norms are in active development.
Interpreting these values
- Values are means from healthy populations; consult primary sources for SDs.
- Dominant hand is typically 5–10% stronger than non-dominant.
- Strength peaks in the late 20s–30s and declines progressively thereafter.
- Different instruments aren't directly comparable without cross-calibration.
Recommended use
Until device-specific norms are published, prefer within-patient serial tracking: establish a baseline at session 1, replicate test conditions at each follow-up, and document change over time as the primary outcome.
Reference Values
Published values for whole-hand finger extension force and whole-hand spread, reproduced from the biomechanics and rheumatology literature.
Published normative data for finger extension and abduction is limited. The values below come from small biomechanics and rheumatology studies, not from clinical norming comparable to Mathiowetz grip and pinch. No published normative data exists for isolated per-digit finger abduction strength, and none is presented here. Prefer within-patient serial tracking over direct comparison.
Finger Extension Force (Whole Hand)
All four fingers together, thumb excluded; MCP joints at a fixed angle, force-transducer measurement (EX-it device). Dominant hand. Values in newtons, as reported.
Brorsson, S., Nilsdotter, A., Sollerman, C., Baerveldt, A.-J., & Hilliges, M. (2008). Technology and Health Care, 16(4), 283–292. Whole-hand values — the source does not report per-digit extension means. Device biomechanics differ from the Splayometer; treat as orientation, not threshold.
Whole-Hand Spread (Multifinger Abduction)
Cumulative four-finger abduction and adduction force — applicable to hand-loop measurement.
Pataky, Latash & Zatsiorsky (2008), n = 21 (12 F / 9 M). Used four independent transducers; hand-loop biomechanics differ — treat as orientation, not threshold.
Evidence-based context
- Extension is a fraction of flexion: in the same young healthy subjects, whole-hand finger extension force averaged 105.1 N in men and 58.7 N in women, against flexion forces of 553.5 N and 320 N — roughly 19% (Brorsson 2008).
- Inter-finger dependence ("enslaving"): activating one finger produces force in adjacent fingers (Zatsiorsky 2000).
- Reduced in rheumatoid arthritis: finger extension force was significantly lower in RA than in age-matched controls — 38.2 N vs. 66.2 N in men (p < 0.05) and 14.8 N vs. 39.1 N in women (p < 0.001) (Brorsson 2008). Extension force also correlated with reported pain level in RA (p < 0.01).
- Flexion stops predicting extension in disease: finger flexion and extension force correlated in healthy women (r = 0.65, p = 0.002) but not in women with RA (r = 0.25, p = 0.289) (Brorsson 2012).
- Whole-hand spread is its own metric: multifinger ab/adduction force is not predictable from single-finger strengths (Pataky 2008).
- Age effects: grip strength peaked within the 25 to 39 age group for both men and women and declined gradually thereafter (Mathiowetz 1985).
Recommended clinical application
Establish a baseline at session 1, replicate test conditions at each follow-up, and track change over time as the primary outcome. No Splayometer-specific minimal detectable change (MDC) has been published — interpret session-to-session variation against your own setup repeatability, not a fixed threshold. For context, published minimal detectable change values for grip dynamometry range from 2.7 to 5.2 kg across three diagnostic groups (Bohannon 2019); no equivalent value has been published for finger extension or abduction.
Comparator Norms & Framework
Established normative datasets and clinical frameworks for context. Click any section to expand.
The most widely cited grip strength norms in North American hand therapy and rehabilitation. Sample: 310 men and 318 women (n = 628) with no known upper extremity pathology. Values are reproduced from the source in pounds, stratified by right and left hand — the source does not report dominant/non-dominant means.
| Age Group | Hand | Men — Mean (lb) | Men — SD | Women — Mean (lb) | Women — SD |
|---|---|---|---|---|---|
| 20–24 | R | 121.0 | 20.6 | 70.4 | 14.5 |
| 20–24 | L | 104.5 | 21.8 | 61.0 | 13.1 |
| 25–29 | R | 120.8 | 23.0 | 74.5 | 13.9 |
| 25–29 | L | 110.5 | 16.2 | 63.5 | 12.2 |
| 30–34 | R | 121.8 | 22.4 | 78.7 | 19.2 |
| 30–34 | L | 110.4 | 21.7 | 68.0 | 17.7 |
| 35–39 | R | 119.7 | 24.0 | 74.1 | 10.8 |
| 35–39 | L | 112.9 | 21.7 | 66.3 | 11.7 |
| 40–44 | R | 116.8 | 20.7 | 70.4 | 13.5 |
| 40–44 | L | 112.8 | 18.7 | 62.3 | 13.8 |
| 45–49 | R | 109.9 | 23.0 | 62.2 | 15.1 |
| 45–49 | L | 100.8 | 22.8 | 56.0 | 12.7 |
| 50–54 | R | 113.6 | 18.1 | 65.8 | 11.6 |
| 50–54 | L | 101.9 | 17.0 | 57.3 | 10.7 |
| 55–59 | R | 101.1 | 26.7 | 57.3 | 12.5 |
| 55–59 | L | 83.2 | 23.4 | 47.3 | 11.9 |
| 60–64 | R | 89.7 | 20.4 | 55.1 | 10.1 |
| 60–64 | L | 76.8 | 20.3 | 45.7 | 10.1 |
| 65–69 | R | 91.1 | 20.6 | 49.6 | 9.7 |
| 65–69 | L | 76.8 | 19.8 | 41.0 | 8.2 |
| 70–74 | R | 75.3 | 21.5 | 49.6 | 11.7 |
| 70–74 | L | 64.8 | 18.1 | 41.5 | 10.2 |
| 75+ | R | 65.7 | 21.0 | 42.6 | 11.0 |
| 75+ | L | 55.0 | 17.0 | 37.6 | 8.9 |
| All subjects | R | 104.3 | 28.3 | 62.8 | 17.0 |
| All subjects | L | 93.1 | 27.6 | 53.9 | 15.7 |
Tip pinch — thumb tip to index fingertip — is the pinch configuration closest to a Splayometer finger-to-thumb measurement, and is reproduced here for comparison. Measured with a B&L pinch gauge. The source also reports key and palmar pinch norms; see the primary paper for those. Values are in pounds, stratified by right and left hand.
| Age Group | Hand | Men — Mean (lb) | Men — SD | Women — Mean (lb) | Women — SD |
|---|---|---|---|---|---|
| 20–24 | R | 18.0 | 3.0 | 11.1 | 2.1 |
| 20–24 | L | 17.0 | 2.3 | 10.5 | 1.7 |
| 25–29 | R | 18.3 | 4.4 | 11.9 | 1.8 |
| 25–29 | L | 17.5 | 5.2 | 11.3 | 1.8 |
| 30–34 | R | 17.6 | 6.7 | 12.6 | 3.0 |
| 30–34 | L | 17.6 | 4.8 | 11.7 | 2.8 |
| 35–39 | R | 18.0 | 3.6 | 11.6 | 2.5 |
| 35–39 | L | 17.7 | 3.8 | 11.9 | 2.4 |
| 40–44 | R | 17.8 | 4.0 | 11.5 | 2.7 |
| 40–44 | L | 17.7 | 3.5 | 11.1 | 3.0 |
| 45–49 | R | 18.7 | 4.9 | 13.2 | 3.0 |
| 45–49 | L | 17.6 | 4.1 | 12.1 | 2.7 |
| 50–54 | R | 18.3 | 4.0 | 12.5 | 2.2 |
| 50–54 | L | 17.8 | 3.9 | 11.4 | 2.4 |
| 55–59 | R | 16.6 | 3.3 | 11.7 | 1.7 |
| 55–59 | L | 15.0 | 3.7 | 10.4 | 1.4 |
| 60–64 | R | 15.8 | 3.9 | 10.1 | 2.1 |
| 60–64 | L | 15.3 | 3.7 | 9.9 | 2.0 |
| 65–69 | R | 17.0 | 4.2 | 10.6 | 2.0 |
| 65–69 | L | 15.4 | 2.9 | 10.5 | 2.4 |
| 70–74 | R | 13.8 | 2.6 | 10.1 | 2.6 |
| 70–74 | L | 13.3 | 2.6 | 9.8 | 2.3 |
| 75+ | R | 14.0 | 3.4 | 9.6 | 2.8 |
| 75+ | L | 13.9 | 3.7 | 9.3 | 2.4 |
| All subjects | R | 17.0 | 4.1 | 11.3 | 2.6 |
| All subjects | L | 16.4 | 4.0 | 10.8 | 2.4 |
Within the Occupational Therapy Practice Framework: Domain and Process (4th ed.; AOTA, 2020), hand strength norms are most relevant to the evaluation of client factors — specifically neuromusculoskeletal and movement-related body functions, including muscle power functions. These body functions underlie performance skills (motor skills) and ultimately support occupational performance across ADLs, work, and leisure.
The OTPF-4 emphasizes that assessment of client factors must always be considered in relation to the client's occupational profile and context. A grip strength value below population norms may or may not be functionally limiting for a given individual, and an above-norm value does not guarantee full occupational participation. Normative data is one input among many in a holistic evaluation (AOTA, 2020).
Bibliography
Sources for the values, framework context, and clinical guidance presented on this page.
- American Occupational Therapy Association. (2020). Occupational therapy practice framework: Domain and process (4th ed.). American Journal of Occupational Therapy, 74(Suppl. 2), 7412410010. https://doi.org/10.5014/ajot.2020.74S2001
- Bohannon, R. W. (2019). Considerations and practical options for measuring muscle strength: A narrative review. BioMed Research International, 2019, 8194537. https://doi.org/10.1155/2019/8194537
- Brorsson, S., Nilsdotter, A., Sollerman, C., Baerveldt, A.-J., & Hilliges, M. (2008). A new force measurement device for evaluating finger extension function in the healthy and rheumatoid arthritic hand. Technology and Health Care, 16(4), 283–292. https://doi.org/10.3233/thc-2008-16406
- Brorsson, S., Nilsdotter, A., Pedersen, E., Bremander, A., & Thorstensson, C. (2012). Relationship between finger flexion and extension force in healthy women and women with rheumatoid arthritis. Journal of Rehabilitation Medicine, 44(7), 605–608. https://doi.org/10.2340/16501977-0986
- Mathiowetz, V., Kashman, N., Volland, G., Weber, K., Dowe, M., & Rogers, S. (1985). Grip and pinch strength: Normative data for adults. Archives of Physical Medicine and Rehabilitation, 66(2), 69–74.
- Mathiowetz, V., Weber, K., Volland, G., & Kashman, N. (1984). Reliability and validity of grip and pinch strength evaluations. Journal of Hand Surgery, 9(2), 222–226. https://doi.org/10.1016/S0363-5023(84)80146-X
- Pataky, T. C., Latash, M. L., & Zatsiorsky, V. M. (2008). Multifinger ab- and adduction strength and coordination. Journal of Hand Therapy, 21(4), 377–385. https://doi.org/10.1197/j.jht.2008.02.002
- Zatsiorsky, V. M., Li, Z. M., & Latash, M. L. (2000). Enslaving effects in multi-finger force production. Experimental Brain Research, 131(2), 187–195. https://doi.org/10.1007/s002219900261
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