Considerations in Cervical Spine and Upper Limb Manual Muscle Testing
Original Editor - Lenie Jacobs
Top Contributors - Lenie Jacobs and Jess Bell
Introduction[edit | edit source]
Muscle strength plays an essential role in facilitating stability and mobility within the musculoskeletal system. Assessing muscle strength is an integral component of the physical examination as it provides an objective measure of a patient's physical strength and offers valuable insights into potential neurological deficits.
When assessing the strength of the cervical spine and upper limb muscles, clinicians should consider various factors that can influence results, including hand dominance, age, biological sex, fatigue, medication, time of day and the patient's occupation. Accounting for these variables is essential to ensure accurate muscle strength evaluations.
If you would like a detailed discussion of the muscle strength assessment, please see: Assessing Muscle Strength.
Hand Dominance[edit | edit source]
Grip strength is considered an indicator of overall strength and a predictor of key outcomes.[1] For instance, low grip strength has been linked to chronic cardiometabolic diseases, neural conditions, reduced function and mobility limitations.[2]
When assessing healthy individuals, it is important to note that the grip strength of the dominant hand is approximately 10% greater than that of the non-dominant hand. This difference is more pronounced in individuals who are right-handed.[1]
Age[edit | edit source]
As individuals age, there is a notable decline in muscle strength, with losses occurring at a rate of approximately 12-14% per decade after the age of 50 years.[3]
- Sarcopenia, a progressive and generalised skeletal muscle disorder, is linked to a heightened risk of adverse outcomes such as falls, fractures, physical disability, and mortality[4]
- Soares et al.[5] found that older, community-dwelling women living in Brazil who have sarcopenia had lower grip strength and respiratory muscle strength compared to their peers who did not have sacropenia[5]
Given these age-related changes, health authorities should consider implementing strength tests, such as grip and leg strength assessments, as screening activities to predict the potential risk of falls and the development of functional disabilities among older adults in the community.[6]
Please watch the following video if you would like to learn more about ageing and muscle mass.
Biological Sex[edit | edit source]
Biological males consistently exhibit higher mechanical muscle function scores compared to females regardless of age.[7] In adult populations, these differences in strength are more pronounced in upper-body muscles than lower-body muscles, and in concentric contractions compared to eccentric contractions. This difference is primarily attributed to the presence of greater muscle mass and larger type II fibre areas in biological males.[8]
The following optional video discusses differences in muscle strength between males and females.
Fatigue[edit | edit source]
The physiological underpinnings of muscle fatigue have been extensively studied. Muscle fatigue can be caused by several different processes, such as the accumulation of metabolites in muscle fibres or inadequate motor commands being generated in the motor cortex.[9]
"The development of muscle fatigue is typically quantified as a decline in the maximal force or power capacity of muscle, which means that submaximal contractions can be sustained after the onset of muscle fatigue."[9]
The impact of fatigue on muscle function is profound. As soon as a muscle's maximal force or power capacity begins to decline, the muscle enters a state of fatigue. When a task involves sustaining a maximal contraction, the decline in performance mirrors the escalation of fatigue.[9]
Yanez et al.[10] compared neuromuscular performance changes in young female university athletes before and after a simulated futsal protocol. They found that changes in neuromuscular performance variables following the simulation protocol resulted in residual muscle fatigue the day after the intervention.[10] These findings shed light on the enduring effects of demanding interventions / exercise on neuromuscular performance and highlight the importance of considering residual fatigue in post-intervention assessments.
Medication[edit | edit source]
Many medications prescribed for commonly occurring conditions can interact with physiological mechanisms, consequently influencing the delicate equilibrium between protein synthesis and degradation. Such interactions can positively and negatively affect muscle mass and strength.[11] Thus, clinicians should determine what medications a patient takes and consider their impact when assessing muscle strength.
To find out more about the impact of medications on sarcopenia and muscle wasting, please see: Oral drugs related with muscle wasting and sarcopenia. A review.
Time of Day[edit | edit source]
There are diurnal variations in skeletal muscle strength, with peak strength typically observed during the late afternoon (i.e. at around 16:00-20:00 / 4-8 pm). This phenomenon occurs in various muscle groups, ranging from the smaller muscles involved in grip strength to the larger elbow and knee muscles. The underlying mechanisms driving these changes in strength throughout the day are still not well defined.[12]
Occupation[edit | edit source]
Occupation can play a role in shaping muscle strength. Different job requirements and physical demands can influence muscle development, function, and health. Research has demonstrated variations in static muscular strength across diverse occupations.[13]
- Chandra et al.[13] found that back strength was significantly lower in video display terminal operators, higher in safety inspectors and moderate in industrial workers, but grip and pinch strength in video display terminal operators, safety inspectors and industrial workers were similar[13]
- Singh et al.[14] found that female handicraft workers might experience higher occupational stress, resulting in decreased grip strength compared to their counterparts in office-based roles
- Hajaghazadeh et al.[15] compared the anthropometric dimensions and hand strength of office workers, vehicle mechanics, and farmers and found that hand strength was lowest in office workers
These articles highlight the nuanced relationship between occupation and muscle strength and emphasise the importance of considering job-specific demands when assessing muscle strength.
Summary[edit | edit source]
Clinicians must remember that the strength of the cervical spine and upper limb muscles can be influenced by various factors such as hand dominance, age, gender, fatigue, medication, time of day and the patient's occupation. As these elements can impact muscle strength testing outcomes, they must be considered when conducting a strength assessment.
References[edit | edit source]
- ↑ 1.0 1.1 Wang YC, Bohannon RW, Li X, Sindhu B, Kapellusch J. Hand-Grip Strength: Normative Reference Values and Equations for Individuals 18 to 85 Years of Age Residing in the United States. Journal of Orthopaedic & Sports Physical Therapy. 2018 Aug 31;48(9):685-93.
- ↑ McGrath R, Johnson N, Klawitter L, Mahoney S, Trautman K, Carlson C, et al. What are the association patterns between handgrip strength and adverse health conditions? A topical review. SAGE Open Med. 2020 Feb 28;8:2050312120910358.
- ↑ Volaklis KA, Halle M, Meisinger C. Muscular strength as a strong predictor of mortality: A narrative review. European Journal of Internal Medicine [Internet]. 2015 Jun 1;26(5):303–10
- ↑ Cruz-Jentoft AJ, Bahat G, Bauer J, Boirie Y, Bruyère O, Cederholm T, et al. Sarcopenia: Revised European Consensus on Definition and Diagnosis. Age and Ageing. 2018 Sep 24;48(1):16–31.
- ↑ 5.0 5.1 Soares LA, Lima LP, Prates ACN, et al. Accuracy of handgrip and respiratory muscle strength in identifying sarcopenia in older, community-dwelling, Brazilian women. Bone. 2023 Jan 27;13(1).
- ↑ Wickramarachchi B, Torabi MR, Perera B. Effects of Physical Activity on Physical Fitness and Functional Ability in Older Adults. Gerontology and Geriatric Medicine. 2023 Feb 23;9:233372142311584.
- ↑ Elam C, Aagaard P, Slinde F, Svantesson U, Hulthén L, Magnusson PS, et al. The effects of ageing on functional capacity and stretch-shortening cycle muscle power. Journal of Physical Therapy Science. 2021 Mar 17;33(3):250–60.
- ↑ Nuzzo JL. Narrative Review of Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations. Journal of Strength and Conditioning Research. 2022 Nov 15;37(2):494–536.
- ↑ 9.0 9.1 9.2 Enoka RM, Duchateau J. Muscle Fatigue: What, Why and How It Influences Muscle Function. The Journal of Physiology [Internet]. 2008 Jan 1;586(1):11–23.
- ↑ 10.0 10.1 Yanez C, Ochoa N, Cardozo L, Jhonatan Peña, Diaz N, Ojeda W, et al. Assessment of Neuromuscular Fatigue 24 hours After a Futsal Simulated Protocol in University Female Athletes. PubMed. 2023 Feb 1;16(1):205–16.
- ↑ Campins L, Camps M, Riera A, Pleguezuelos E, Yebenes JC, Serra-Prat M. Oral Drugs Related with Muscle Wasting and Sarcopenia. A Review. Pharmacology. 2016 Aug 31;99(1-2):1–8.
- ↑ Douglas CM, Hesketh SJ, Esser KA. Time of Day and Muscle Strength: A Circadian Output? Physiology. 2020 Dec 16;36(1):44–51.
- ↑ 13.0 13.1 13.2 Chandra AM, Ghosh S, Iqbal R, Sadhu N. A Comparative Assessment of the Impact of Different Occupations on Workers’ Static Musculoskeletal Fitness. International Journal of Occupational Safety and Ergonomics. 2007 Jan;13(3):271-8.
- ↑ Singh AK, Meena ML, Chaudhary H, Dangayach GS. A comparative assessment of static muscular strength among female operative’s working in different handicraft occupations in India. Health Care for Women International. 2018 Dec 20;40(4):459-78.
- ↑ Hajaghazadeh M, Taghizadeh M, Mohebbi I, Khalkhali H. Hand anthropometric dimensions and strengths in workers: A comparison of three occupations. Human Factors and Ergonomics in Manufacturing and Service Industries. 2022;32:373-88.
