Sarcopenia in Older Adults: Strength Exercise and Functional Independence

Sarcopenia — the progressive loss of muscle mass and strength associated with ageing — is one of the main factors compromising the functional independence of older adults. Its impact goes far beyond muscle weakness: it is associated with a higher risk of falls, fractures, hospitalisation, institutionalisation and mortality. In people with neurological pathology — such as stroke or Parkinson's disease — sarcopenia may accelerate significantly, complicating rehabilitation and compromising functional recovery.

In this clinical guide we review the updated definition of sarcopenia according to EWGSOP2 criteria, its diagnosis, the evidence on resistance/strength exercise as a first-line intervention, the role of nutrition and the implications for clinical practice in neurorehabilitation.

1. Definition of sarcopenia: EWGSOP2 criteria

In 2019, the European Working Group on Sarcopenia in Older People published an update to its consensus (EWGSOP2), which represented an important conceptual shift in the definition and approach to sarcopenia (Cruz-Jentoft et al., 2019). Sarcopenia moved from being considered a condition exclusively linked to ageing to being recognised as a progressive muscle disorder that can be primary (age-related) or secondary (associated with inactivity, malnutrition or chronic diseases).

According to EWGSOP2 criteria, sarcopenia is defined at three levels:

• Probable sarcopenia: identified when there is low muscle strength, measured by handgrip dynamometry (cut-off point: <27 kg in men, <16 kg in women) or the chair stand test (5 repetitions in >15 seconds).
• Confirmed sarcopenia: when, in addition to low strength, low muscle quantity or quality is demonstrated by techniques such as dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) or computed tomography (CT).
• Severe sarcopenia: when the previous criteria are accompanied by low physical performance, assessed with tests such as gait speed (≤0.8 m/s), Short Physical Performance Battery (SPPB, ≤8 points), Timed Up and Go (TUG, ≥20 seconds) or the 400-metre walk test.

A key aspect of the EWGSOP2 update is that it positions muscle strength — not muscle mass — as the primary parameter for screening and diagnosis, given that low strength is a more consistent predictor of adverse outcomes than low muscle mass alone.

2. Prevalence of sarcopenia

The prevalence of sarcopenia varies considerably according to the population studied, diagnostic criteria used and care setting. The most frequently cited figures in the literature are:

• Community-dwelling older adults: between 5% and 13% in adults over 60, according to the meta-analysis by Petermann-Rocha et al. (2022). Prevalence progressively increases with age, exceeding 20% in adults over 80.
• Institutionalised individuals: prevalence can reach 30–50% in care homes, where physical inactivity, malnutrition and comorbidities converge to accelerate muscle loss.
• Hospitalised patients: it is estimated that between 15% and 40% of older hospitalised patients have sarcopenia, which is associated with longer stays, higher risk of complications and worse functional prognosis.

Sarcopenia and neurological pathology

In people with neurological diseases, sarcopenia has a particularly high prevalence and an accelerated progression pattern:

• Stroke: immobilisation, spasticity, paresis and neuroendocrine dysregulation can contribute to rapid muscle loss in the affected side. Various studies have described that up to 40–60% of stroke survivors meet sarcopenia criteria in the chronic phase (Scherbakov et al., 2013). This muscle loss can limit rehabilitation possibilities and compromise recovery of gait and activities of daily living.
• Parkinson's disease: reduced physical activity, postural changes, dysphagia (which can compromise protein intake) and chronic neuroinflammatory mechanisms are associated with higher prevalence of sarcopenia in this population. Loss of muscle strength may contribute to worsening balance and higher risk of falls, a central problem in Parkinson's disease.

Sarcopenia is not an inevitable consequence of ageing. It is a muscle disorder that can be diagnosed, prevented and treated — and resistance/strength exercise is the intervention with the highest level of evidence for its management.

3. Diagnosis: tools and tests

The diagnostic algorithm proposed by EWGSOP2 establishes a stepwise process that can be implemented in routine clinical practice:

Screening

The SARC-F questionnaire is the recommended screening tool. It consists of 5 questions about strength, walking assistance, rising from a chair, climbing stairs and falls. A score ≥4 suggests risk of sarcopenia and justifies a more detailed assessment. It is simple, quick and can be self-administered, although its sensitivity is moderate.

Muscle strength assessment

• Handgrip dynamometry: the most widely used test, recommended as the first diagnostic step. It is performed with a calibrated hydraulic dynamometer (Jamar type). EWGSOP2 cut-off points are <27 kg in men and <16 kg in women.
• Chair Stand Test: 5 repetitions in more than 15 seconds indicate low lower limb strength. Particularly useful when handgrip dynamometry is not feasible (for example, in patients with severe arthritis or hand paresis).

Muscle mass assessment

• DXA (dual-energy X-ray absorptiometry): considered the reference method in research. Measures appendicular lean mass, adjusted for height or BMI.
• BIA (bioelectrical impedance analysis): a portable and more accessible alternative to DXA. Useful in outpatient clinical practice, although its accuracy may be affected by hydration status.

Physical function assessment

• SPPB (Short Physical Performance Battery): assesses balance, gait speed and ability to rise from a chair. A score ≤8 out of 12 indicates low physical function.
• Gait speed: measured over a 4-metre course. A speed ≤0.8 m/s is considered indicative of low physical function and is associated with adverse outcomes.
• TUG (Timed Up and Go): measures the time taken for the person to stand up from a chair, walk 3 metres, turn and sit back down. A time ≥20 seconds suggests significant functional limitation.

4. Resistance/strength exercise: first-line treatment

Progressive resistance training (also called resistance training or strength training) is, according to available evidence, the most effective intervention for managing sarcopenia. Its capacity to stimulate muscle hypertrophy, improve strength and optimise neuromuscular function is supported by multiple systematic reviews and high-quality meta-analyses:

• Liu and Latham (2009), Cochrane: this systematic review, which included 121 randomised clinical trials with more than 6,700 older participants, concluded that progressive resistance training produces significant improvements in muscle strength (large effect size), as well as moderate improvements in functional activities, such as rising from a chair, gait speed and climbing stairs. Serious adverse events were infrequent.
• Peterson et al. (2010): in a meta-analysis analysing 49 studies with 1,328 participants, significant gains in lean mass and muscle strength were confirmed in older adults performing resistance training, with more pronounced effects in high-intensity programmes.
• Landi et al. (2014): this review highlighted that resistance/strength exercise, especially when combined with adequate protein intake, can contribute to partially reversing sarcopenia and improving functional capacity in older adults, including the most frail.

It is important to note that the magnitude of the response to resistance training varies between individuals and depends on factors such as age, baseline muscle function level, comorbidities, programme adherence and nutritional quality. Nevertheless, evidence consistently supports that resistance/strength exercise can contribute to improving muscle strength and function even in very advanced age.

5. Resistance/strength training prescription

International guidelines and the scientific literature converge on the following recommendations for resistance/strength training prescription in older adults with or at risk of sarcopenia:

Prescription parameters

• Frequency: 2–3 sessions per week, with at least 48 hours of rest between sessions for the same muscle group.
• Intensity: 60–80% of the maximum repetition (1RM). In people with significant functional limitations or starting the programme, beginning with lower intensities (40–60% 1RM) is recommended, progressing gradually.
• Volume: 2–3 sets of 8–12 repetitions per exercise, with rest periods of 1–2 minutes between sets.
• Type of exercises: multi-joint exercises involving large muscle groups are prioritised — squats (assisted if necessary), leg press, lifts, pushes and pulls — for their greater functional transfer.
• Progression: gradual load progression is a fundamental principle. When the person can complete the prescribed repetitions with good technique and without pain, the load is increased by 5–10%.

Safety considerations

Supervision by qualified professionals is essential, especially in the initial phases and in people with comorbidities. Training should be adapted to individual capabilities, avoiding excessive Valsalva manoeuvres in people with uncontrolled hypertension or cardiovascular disease. Correct technique and individualised progression can contribute to minimising the risk of musculoskeletal injuries.

6. Nutrition: the necessary complement

Nutritional intervention is an indispensable complementary pillar to resistance/strength exercise in addressing sarcopenia. Evidence suggests nutritional strategies can enhance the effects of training when implemented together:

Proteins

• Recommended intake: 1.0–1.2 g of protein/kg/day for healthy older adults, and up to 1.2–1.5 g/kg/day in the presence of sarcopenia or acute illness (Bauer et al., 2013; Deutz et al., 2014). These figures exceed the general recommendation of 0.8 g/kg/day, which may be insufficient to maintain muscle mass in older adults.
• Distribution: distributing protein intake evenly across main meals (25–30 g per meal) may contribute to optimising muscle protein synthesis throughout the day.
• Leucine: this essential branched-chain amino acid plays a prominent role in activating the mTOR pathway and stimulating muscle protein synthesis. Rich sources of leucine include dairy, eggs, meat, fish and legumes.

Vitamin D

Vitamin D deficiency is highly prevalent in older adults and is associated with greater risk of sarcopenia, muscle weakness and falls. Guidelines recommend maintaining serum 25-hydroxyvitamin D levels above 50 nmol/L (20 ng/mL), resorting to supplementation when necessary and under medical supervision.

Nutritional timing

Protein intake in a window close to resistance/strength training (within 2 hours afterwards) may contribute to maximising the muscle anabolic response. However, evidence on optimal timing is less robust than that relating to total protein quantity, and adherence to adequate daily protein intake remains the priority.

7. Impact on functional independence and falls prevention

Sarcopenia is a determinant factor in the loss of functional independence in older adults. Muscle weakness limits the ability to perform basic activities — rising from a chair, climbing stairs, walking autonomously — and significantly increases the risk of falls and fractures.

The Cochrane review by Sherrington et al. (2019), which included 108 clinical trials with more than 23,000 older participants, concluded that exercise programmes including balance and resistance/strength training can reduce the rate of falls by approximately 23%. This review represents one of the most solid evidence bases in the field of falls prevention and supports the inclusion of resistance/strength exercise as an essential component of preventive programmes.

The benefits of resistance/strength exercise on functional independence can manifest in multiple dimensions:

• Improved walking capacity: strengthening of lower limb musculature may contribute to increasing gait speed, a key indicator of functionality and predictor of survival in older adults.
• Improved balance: resistance/strength training, especially of proximal and trunk musculature, may contribute to improving postural control and reducing falls risk.
• Autonomy in activities of daily living: strength gains may facilitate transfers (sit-to-stand), climbing and descending stairs, and other activities essential for independent living.
• Reduction of institutionalisation risk: preservation of muscle function is associated with a lower probability of needing long-term institutional care.

8. The GNeuro programme: adapted strength training in Ourense

At GNeuro, a robotic neurorehabilitation clinic in Ourense, we integrate supervised resistance/strength training as a central component of our programmes aimed at older adults and neurological patients with sarcopenia or risk of sarcopenia.

Our approach is characterised by:

• Individualised functional assessment: we carry out an initial assessment including handgrip dynamometry, functional tests (SPPB, TUG, gait speed) and nutritional assessment, to establish the starting point and objectives for each person.
• Progressive and supervised strength programmes: programmes are designed individually, with gradual load progression and continuous professional supervision, adapting to each participant's capabilities and limitations.
• Robotic technology as a complement: the robotic technology available at GNeuro — robotic gait training system, upper limb rehabilitation robot — can contribute to complementing conventional strength training, allowing high-repetition training with precise load and assistance control.
• Multidisciplinary approach: the intervention combines resistance/strength exercise with nutritional advice and, when necessary, coordination with the rehabilitation physician for a comprehensive approach to sarcopenia.
• Specific care for neurological patients: in people with stroke, Parkinson's disease or other neurological conditions, programmes are adapted to address both sarcopenia and specific neurological limitations, with the aim of maximising functional recovery.

Frequently asked questions

References