1. Why this article?
Many people notice the same things. Getting out of an armchair suddenly takes longer. The shopping bag feels heavier. Running for the bus is no longer an option. And the explanation you usually hear is: “that is just age”.
That is half the truth. Yes, muscles change with age. No, the extent of it is not fate. The difference between an 80-year-old who lives independently and someone of the same age who needs help has a great deal to do with muscle strength — and muscle strength is one of the few aspects of ageing you can influence very concretely.
This article explains what happens in your body, how muscle weakness is recognised and what is proven to help. Every statement is referenced. The numbers in square brackets refer to the reference list at the end.
2. What is sarcopenia?
“Sarcopenia” comes from the Greek: sarx means flesh, penia means lack. It refers to a loss of muscle strength and muscle mass that goes beyond the normal extent.
The key point first: in 2019 the European working group fundamentally revised its definition and has since described sarcopenia as a muscle disease — comparable to the way osteoporosis is described as a bone disease [1]. That is not a matter of wording. It means sarcopenia has a diagnosis, it has consequences, and it can be treated.
2.1 Strength counts for more than size
Until a few years ago muscle mass was at the centre. What was measured was how much muscle someone has. Today muscle strength comes first [1]. The reason is simple: strength is a far better predictor of how someone manages in daily life.
This also explains an observation that surprises many people: some look muscular and are still weak. And slim people can be remarkably strong. Muscle size on its own is a poor guide.
2.2 The three stages
Clinicians distinguish three stages [1]:
Probable sarcopenia — muscle strength is reduced. This is measured, for example, with grip strength (reference values: below 27 kg in men, below 16 kg in women) or with a chair-rise test (rising from a chair five times takes longer than 15 seconds). This finding alone is enough to start treatment.
Confirmed sarcopenia — muscle mass is reduced as well. This is measured with specific equipment, usually a bone density scan (DXA) or a body composition scale of medical standard.
Severe sarcopenia — physical performance is impaired on top of that, for instance gait speed (reference value: 0.8 metres per second or slower).
These figures are reference values, not verdicts. They serve comparisons in studies and orientation in practice — not as a label for a person.
2.3 A word on the terminology
You may come across further terms. In brief:
- Dynapenia: the loss of maximal strength. That is: how much weight can you move at all?
- Powerpenia, or loss of muscle power: the ability to produce force quickly. That is: how fast can you move the weight?
This distinction is not academic. It has direct consequences for training — more on that below.
3. How common is sarcopenia?
A large worldwide review pooled data from more than 690,000 people. Depending on the definition used, the prevalence in people aged 60 and over lies between 10 and 27 per cent. Severe sarcopenia affects 2 to 9 per cent [2].
That range looks unsatisfying, but it is honest: different working groups use different cut-off points, and those cut-offs help determine how many people count as affected. It is also notable that Europe sits towards the lower end of this analysis and Oceania towards the upper end [2]. That is likely to reflect differences in body build and differently calibrated cut-offs.
There are no large representative figures for Switzerland. The European order of magnitude serves as orientation: roughly one in eight to one in five people over 60 is affected. In nursing homes and in hospital the figures are considerably higher.
4. Why do muscles get weaker with age?
There is no single reason. Several processes run in parallel and reinforce one another. Here are the most important ones — as simple as possible, but not simpler.
4.1 The nerves withdraw
Every muscle is controlled by nerve cells. A nerve cell plus the muscle fibres it supplies is called a motor unit. You can picture it as a street lamp with its power cable.
From about the age of 60 onwards, such nerve cells are increasingly lost. The muscle fibres they supplied are then “unconnected”. Neighbouring nerve cells take over some of them — but not all, and not with the same fine control as before. Reviews describe this loss of innervation as one of the main reasons for muscle wasting in old age [3].
Two consequences matter:
First, we lose muscle mass, because orphaned fibres disappear.
Second — and this is often overlooked — we lose fine control and speed. The fast muscle fibres (type II) are affected in particular. Those are precisely the fibres you need when you trip and have to put out a step within a fraction of a second.
4.2 The muscle responds less strongly to protein
Your body is constantly building up and breaking down muscle protein. After a protein-rich meal, build-up increases. With age, however, that increase is smaller than in younger years. Specialists call this anabolic resistance — the muscle responds less sensitively to the stimulus [4].
In practical terms: an older person needs more protein per meal than a young one to produce the same building stimulus. That is exactly why protein recommendations for older people are higher than the general values [5].
4.3 Fat moves into the muscle
Over the years, fat is deposited between and within the muscle fibres. On a scan the muscle then looks rather marbled. Working groups summarise this under the heading of “muscle quality” [1].
This point explains an apparent contradiction: why does someone lose more strength than the loss of mass would explain? Because part of what is still visible as “muscle” is no longer functioning muscle tissue.
4.4 Silent inflammation and hormones
With age, certain inflammatory messengers in the blood rise slightly — permanently, at a low level. Specialists speak of inflamm-aging. These messengers promote protein breakdown and slow build-up [3]. Hormonal changes come on top, in women particularly after the menopause.
Both factors are less directly modifiable than exercise and nutrition — but exercise has a favourable effect on them too.
4.5 Inactivity — the strongest accelerator
This is the most important section in this chapter.
When a muscle is not loaded, it breaks down. That is true at any age. In older age it hits harder, because anabolic resistance is added to it: the loss is fast, the rebuild is slow [4].
Concretely: a week of flu in bed, an operation followed by rest, a hospital stay, a broken wrist, a very rainy month with few walks — none of these are harmless pauses. They are events after which, without targeted training, part of the lost strength often does not come back on its own.
The most important sentence in this article may therefore be this one: it is not ageing that costs the most strength, but the weeks in which we do not move.
5. Strength, power, and why the difference matters
Picture two tasks.
Task A: you lift a full crate of drinks from the floor onto the table. That is strength — a lot of weight, moved slowly.
Task B: you trip and have to straighten the supporting leg and place the other foot forward within a fraction of a second. That is power — force times velocity.
Both abilities decline with age. But power declines earlier and faster. In a large European study of more than 9,000 people aged 60 and over, sit-to-stand power relative to body weight fell markedly from around the age of 50 onwards [9].
That study also provides reference values for when it becomes critical: below 2.1 watts per kilogram of body weight in women and below 2.6 watts per kilogram in men, the risk of mobility limitations was clearly increased [9]. The value can be calculated from a simple chair-rise test — your physiotherapist can do that in a few minutes.
Why this matters in daily life: almost every critical situation is a power situation. A fall gives no warning. The bus does not slow down. The step does not arrive later. Anyone who can only build force slowly loses out in exactly those moments.
6. What sarcopenia means in daily life
Muscle weakness is rarely a sudden event. It shows up in small changes that are easily explained away:
- You push off the armrests when standing up — occasionally at first, then always.
- You hold the handrail on the stairs, even though you did not need it before.
- You plan your routes so that you never have to walk fast.
- You carry the shopping in two trips.
- You avoid uneven ground.
- You take longer to feel “like before” after a cold.
Each of these adaptations is sensible in itself. Together, however, they form a cycle: less strength leads to less activity, less activity leads to less strength. That is precisely the cycle described in the literature on frailty [16].
The good news: a cycle can be broken at any point.
7. Sarcopenia, frailty, cachexia — three things that are often confused
These three terms sound similar and mean different things.
Sarcopenia is a muscle disease. It is defined by reduced strength and mass. People of normal weight and without any known underlying condition can be affected too [1].
Frailty is broader. It describes reduced resilience across several body systems: muscles, but also exhaustion, unintentional weight loss, reduced activity and further domains. People with frailty recover more slowly and less completely after a stress such as an operation or an infection [16]. Sarcopenia is often the physical core of frailty — but not the whole of it.
Cachexia is disease-driven wasting — typically in advanced cancer, heart failure, COPD or kidney failure. Its hallmarks are pronounced, unintentional weight loss and strong inflammatory activity. Unlike “pure” sarcopenia, cachexia cannot primarily be reversed through training and protein, because the underlying disease dominates.
Why the distinction matters: it determines where treatment puts its emphasis. In sarcopenia, strength training is central. In frailty, several building blocks are added. In cachexia, treating the underlying disease comes first.
One particular constellation is sarcopenic obesity: little muscle mass alongside a lot of body fat. It is treacherous because body weight conceals the muscle loss — the scales show nothing remarkable, while the muscles perform less well and have to carry more weight at the same time.
8. How can you assess it yourself?
There is a simple questionnaire used worldwide: the SARC-F. It was developed in 2013 [14] and exists in a validated German version [15].
Five questions, 0 to 2 points each:
- Strength — how much difficulty do you have lifting and carrying about 4.5 kg?
None = 0 · Some = 1 · A lot, or unable = 2 - Assistance in walking — how much difficulty do you have walking across a room?
None = 0 · Some = 1 · A lot, only with an aid, or unable = 2 - Rising from a chair — how much difficulty do you have getting up from a chair or bed?
None = 0 · Some = 1 · A lot, or only with help = 2 - Climbing stairs — how much difficulty do you have climbing ten steps?
None = 0 · Some = 1 · A lot, or unable = 2 - Falls — how often have you fallen in the past year?
Never = 0 · One to three times = 1 · Four times or more = 2
Scoring: from 4 points upwards the test counts as positive. That is a reason to raise the topic with your GP or in physiotherapy.
And now the honest appraisal
This test is convenient — but imprecise. In the German validation study it detected probable sarcopenia with a sensitivity of 75 per cent and a specificity of 67 per cent. For confirmed sarcopenia the values were considerably worse: 63 per cent sensitivity, 47 per cent specificity [15].
Translated, that means:
- A negative result does not rule out sarcopenia. About a quarter of those affected are missed.
- A positive result proves nothing. It is a pointer, not a finding.
So the test does not replace an examination. It opens a conversation — no more than that, but no less either.
Two additional observations
The chair-rise test. Sit on an ordinary chair, cross your arms in front of your chest and stand up and sit down five times as fast as possible. If that takes longer than 15 seconds, it counts as a sign of reduced muscle strength [1]. Only do this test if you feel safe doing so, and place the chair against a wall.
Calf circumference. Measure at the thickest part of the calf. Very small values are a sign of reduced muscle mass. Cut-off points differ between studies, which is why we deliberately give no figure here — that measurement belongs in a conversation with a professional.
9. What really helps
Here comes the most important part. And the message is pleasingly clear.
9.1 Strength training — the foundation
There are few treatments in medicine whose effect is as well established as strength training in older people.
The best-known study dates from 1994. One hundred nursing home residents — mean age 87 years, the oldest 98 — completed ten weeks of progressive resistance training. A nutritional supplement was tested alongside it. The result: training clearly improved strength and function. The supplement alone did not [6].
That was more than thirty years ago. The finding has been confirmed many times since and is now part of international recommendations [12].
What does that mean for you? It is never too late. At 85 as well, after a hospital stay as well, with osteoarthritis as well, with heart disease as well. Adapting the programme is the professional's job — not a reason to leave it be.
9.2 How intensive, how often?
For healthy older people, a dose-response analysis of 25 studies identified the following ranges as favourable: a load of roughly 70 to 79 per cent of maximal strength, about six seconds of time under tension per repetition and around one minute of rest between sets [7].
For people whose capacity is already reduced, things look somewhat different. An analysis of studies in frail and pre-frail people showed that resistance training improves chair rising and general physical performance. It takes at least two training sessions per week to do so. And — notably — a very high training volume per session produced no better results [8].
That is a reassuring message. You do not have to spend hours in the gym. Two to three short but properly dosed sessions per week are the load-bearing pillar.
9.3 What “properly dosed” means in practice
Percentages of maximal strength are impractical in daily life — nobody performs a maximum test at home. A simpler approach:
Choose a weight or a resistance that lets you manage 8 to 12 clean repetitions. At the end of the set you should have the feeling: two to four more repetitions would have been possible — no more than that.
If you suddenly manage 15 repetitions without effort, the load has become too light. Then it is increased. This step-by-step increase is precisely the active ingredient. Training with the same resistance band for two years is no longer strength training — it is a habit.
A common mistake: stopping too early. Most people markedly underestimate at first how many repetitions they could still have done. That self-assessment can be trained — best of all in the first few therapy sessions together with a professional.
9.4 Training power as well
Because power is lost earlier and faster, it is worth training it specifically.
The evidence on this is positive but nuanced. An early meta-analysis from our own circle compared power training with conventional resistance training in people over 60 and found a small advantage for power training in everyday function [10]. A more recent and larger analysis of 20 studies with 566 people also found an advantage — though the authors rate the certainty of that statement as low [11].
Honestly: the difference between the two forms of training is smaller than the difference between “training” and “not training”. Both work. Combining them does nothing wrong.
In practice, power training is simpler than it sounds. It is not about waving light weights around. It is about the intention to accelerate briskly: the upward movement as fast as possible, the downward movement controlled and slow. Rising from a chair, that means: up briskly, down slowly.
9.5 Not just strength: the whole package
Pure strength training is the core, but not the whole answer. A 2024 review found a clear reduction in frailty risk for multicomponent programmes — strength plus balance plus endurance. For nutritional supplements, by contrast, the effect remained unclear [13].
A sensible weekly programme therefore contains:
- Strength training, two to three times a week, for legs, trunk and arms
- Balance exercises, ideally daily, even briefly — standing at the kitchen counter while the coffee brews
- Endurance, that is brisk walking, cycling or swimming
- Everyday movement that nobody would call training: stairs instead of the lift, getting off one stop earlier, working in the garden
All of these building blocks also appear in the international recommendations on physical activity in older age [12].
9.6 Protein: important, but no substitute
Muscles need building material. Because older muscles respond less strongly to protein [4], the recommendations are higher than they used to be.
The European society for clinical nutrition recommends at least 1.0 to 1.2 grams of protein per kilogram of body weight per day for healthy older people. During illness or recovery after a hospital stay the requirement is higher [5].
For a person weighing 70 kg that is roughly 70 to 85 grams a day. For orientation: that corresponds to about a tub of quark, a portion of fish or meat, an egg and a portion of pulses — spread across the day.
Two practical points:
Spread the protein across the day. Many people eat almost none in the morning and a great deal in the evening. Spread across the day you use the building stimulus several times instead of only once.
Protein without training achieves little. The 1994 study already showed this [6] and more recent analyses confirm it [13]. The building material is only of use once there is a stimulus that starts the building.
Different rules apply in kidney disease — in that case discuss the amount of protein with your doctor.
10. The critical weeks: a plan for periods of illness
Because inactivity is the strongest accelerator [4], it pays to deal deliberately with exactly those phases in which you least feel like moving.
With a cold or flu: rest is right. But as soon as the fever is gone, every day counts. Stand up regularly. Do a few sit-to-stand movements from a chair, several times a day.
Before planned surgery: the weeks beforehand are valuable. Going into an operation with more strength means more reserve for afterwards.
In hospital: ask actively about physiotherapy and about whether you are allowed to get up. Sitting in a chair is better than lying down. Walking in the corridor is better than sitting. Clarify the safety questions with the staff — but do not let the matter drop.
After the hospital stay: this is the decisive phase. Part of the lost strength does not return without targeted training. This is the best moment for a structured build-up programme.
With a broken arm or leg: the cast concerns one part of the body — not the whole of it. The healthy side and the trunk can and should carry on training.
11. Five common misconceptions
“Muscle loss in old age is normal, there is nothing to be done.”
A certain decline is normal. Its extent is not. The difference between unavoidable ageing and avoidable decline lies exactly where training and nutrition take effect [1], [12].
“Strength training is too dangerous for old people.”
Progressive resistance training has been carried out in studies with people of a mean age of 87 in a nursing home [6] and is part of international recommendations [12]. More dangerous than training is the loss of strength that leads to falls.
“I move enough — I go for a walk every day.”
Walking is valuable for the heart, the circulation and mood. As a stimulus for building muscle, however, it is not sufficient. The muscle needs a load clearly above everyday demands. Walking and strength training are two different things — both are needed.
“Protein powder solves the problem.”
Nutritional supplementation alone showed no functional improvement in the classic study [6], and in current reviews the effect of supplements remains unclear [13]. Protein supports training — it does not replace it.
“I am not underweight, so I do not have sarcopenia.”
Body weight says little about muscle strength. In sarcopenic obesity a high weight even conceals the muscle loss. The scales are a poor guide here — a chair-rise test is a better one.
12. When should you consult a professional?
Raise the topic if one or more of these statements apply:
- The SARC-F self-test gives 4 points or more
- Rising from a chair five times takes longer than 15 seconds
- You have fallen in the past year, or you are afraid of falling
- You have lost weight unintentionally
- You do not feel “like before” again after an illness or an operation
- You have recently started pushing off when standing up
- You avoid activities you used to do as a matter of course
What to expect in physiotherapy: a grip strength measurement, a chair-rise test, a gait speed measurement and, where appropriate, the calculation of relative sit-to-stand power against the European reference values [9]. From this comes an individual training programme with clear progression steps and — this matters — a home programme that you carry out yourself between appointments.
What belongs in a medical work-up: unintentional weight loss, newly arisen severe exhaustion, suspected malnutrition, thyroid disease, anaemia, or a medication list that has grown too long. Muscle weakness sometimes has treatable causes that have nothing to do with age.
13. In summary
Muscle weakness in old age is common, consequential — and modifiable to an unusually high degree.
You do not need equipment costing thousands of francs, nor an hour of training every day. You need two to three strength sessions a week in which the load genuinely demands something and increases over time. You need enough protein, spread across the day. You need attention for the weeks in which you are ill or immobile. And you need the willingness to stop accepting “that is just age” as an explanation.
Muscle is one of the most adaptable tissues in the body. It responds at 30, and it responds at 90. More slowly — but it responds.
If you would like to explore the topic playfully: our quiz Sarcopenia facts goes through the same points in 13 questions.
References
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[1] Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age and Ageing. 2019;48(1):16–31. https://doi.org/10.1093/ageing/afy169
[2] Petermann-Rocha F, Balntzi V, Gray SR, et al. Global prevalence of sarcopenia and severe sarcopenia: a systematic review and meta-analysis. Journal of Cachexia, Sarcopenia and Muscle. 2022;13(1):86–99. https://doi.org/10.1002/jcsm.12783
[3] Larsson L, Degens H, Li M, et al. Sarcopenia: Aging-Related Loss of Muscle Mass and Function. Physiological Reviews. 2019;99(1):427–511. https://doi.org/10.1152/physrev.00061.2017
[4] Nunes EA, Stokes T, McKendry J, Currier BS, Phillips SM. Disuse-induced skeletal muscle atrophy in disease and nondisease states in humans: mechanisms, prevention, and recovery strategies. American Journal of Physiology – Cell Physiology. 2022;322(6):C1068–C1084. https://doi.org/10.1152/ajpcell.00425.2021
[5] Volkert D, Beck AM, Cederholm T, et al. ESPEN practical guideline: Clinical nutrition and hydration in geriatrics. Clinical Nutrition. 2022;41(4):958–989. https://doi.org/10.1016/j.clnu.2022.01.024
[6] Fiatarone MA, O'Neill EF, Ryan ND, et al. Exercise training and nutritional supplementation for physical frailty in very elderly people. New England Journal of Medicine. 1994;330(25):1769–1775. https://doi.org/10.1056/NEJM199406233302501
[7] Borde R, Hortobágyi T, Granacher U. Dose-Response Relationships of Resistance Training in Healthy Old Adults: A Systematic Review and Meta-Analysis. Sports Medicine. 2015;45(12):1693–1720. https://doi.org/10.1007/s40279-015-0385-9
[8] Nagata CA, Garcia PA, Hamu TCDS, et al. Are dose-response relationships of resistance training reliable to improve functional performance in frail and pre-frail older adults? A systematic review with meta-analysis and meta-regression of randomized controlled trials. Ageing Research Reviews. 2023;91:102079. https://doi.org/10.1016/j.arr.2023.102079
[9] Alcazar J, Alegre LM, Van Roie E, et al. Relative sit-to-stand power: aging trajectories, functionally relevant cut-off points, and normative data in a large European cohort. Journal of Cachexia, Sarcopenia and Muscle. 2021;12(4):921–932. https://doi.org/10.1002/jcsm.12737
[10] Tschopp M, Sattelmayer MK, Hilfiker R. Is power training or conventional resistance training better for function in elderly persons? A meta-analysis. Age and Ageing. 2011;40(5):549–556. https://doi.org/10.1093/ageing/afr005
[11] Balachandran AT, Steele J, Angielczyk D, et al. Comparison of Power Training vs Traditional Strength Training on Physical Function in Older Adults: A Systematic Review and Meta-analysis. JAMA Network Open. 2022;5(5):e2211623. https://doi.org/10.1001/jamanetworkopen.2022.11623
[12] Izquierdo M, de Souto Barreto P, Arai H, et al. Global consensus on optimal exercise recommendations for enhancing healthy longevity in older adults (ICFSR). The Journal of Nutrition, Health and Aging. 2025;29(1):100401. https://doi.org/10.1016/j.jnha.2024.100401
[13] Sirikul W, Buawangpong N, Pinyopornpanish K, Siviroj P. Impact of multicomponent exercise and nutritional supplement interventions for improving physical frailty in community-dwelling older adults: a systematic review and meta-analysis. BMC Geriatrics. 2024;24(1):958. https://doi.org/10.1186/s12877-024-05551-8
[14] Malmstrom TK, Morley JE. SARC-F: a simple questionnaire to rapidly diagnose sarcopenia. Journal of the American Medical Directors Association. 2013;14(8):531–532. https://doi.org/10.1016/j.jamda.2013.05.018
[15] Drey M, Ferrari U, Schraml M, et al. German Version of SARC-F: Translation, Adaption, and Validation. Journal of the American Medical Directors Association. 2020;21(6):747–751.e1. https://doi.org/10.1016/j.jamda.2019.12.011
[16] Kim DH, Rockwood K. Frailty in Older Adults. New England Journal of Medicine. 2024;391(6):538–548. https://doi.org/10.1056/NEJMra2301292