Cycling and strength training: the combination that interferes least

There is a point in life when the bike suddenly becomes the sensible choice. The knee grumbles after your runs. The Achilles is stiff for the first hundred metres every morning. Then one day you take the bike to work instead, arrive warm and out of breath with nothing hurting, and think: why have I been doing the other thing?

That is a perfectly reasonable thought. Cycling is excellent endurance training and it is kind to joints that have taken a beating for twenty-five years. This page is about what happens when you put it next to strength training: why the two go together unusually well, and what the bike does not do for you that has to be covered somewhere else.

Why cycling and strength training get along better than running and strength training

The question of whether endurance work blunts strength work has a name in the research, the interference effect, and it is worked through in detail in the guide to strength training and running. The short version is that the effect is real but narrower than its reputation.

What matters here is how it is distributed. A meta-analysis of 21 studies with 422 effect sizes set out to identify which components of endurance training actually drag down the results of resistance training. When the researchers split the material by the type of endurance work involved, the answer fell one way: resistance training combined with running produced statistically significant decrements in both hypertrophy and strength. Resistance training combined with cycling did not.

The same analysis found that both the frequency and the duration of endurance sessions correlated negatively with the outcomes. Interference is a dose, not a switch. But modality is the variable that comes through most clearly, and it is the one that makes cycling a favourable choice for anyone trying to get stronger at the same time.

The difference is in the braking

Why running in particular? The most obvious explanation is mechanical. A running stride contains a moment where the muscle works while it is being lengthened, braking the landing. Multiplied by thousands of steps, that adds up to a substantial amount of the kind of work the body takes longest to repair. It is also the kind of work behind delayed onset muscle soreness.

Pedalling looks different. Your foot never meets the ground, the crank goes round, and the muscle works almost entirely by contracting. There is barely any braking to recover from. That is why your legs can be tired after a long ride without being broken down the way a long run in the woods breaks them down.

Cycling's blind spot: your skeleton

Here is the part that almost never appears in cycling articles, and it matters most if you are over 40.

The starting point is not controversial. The NHS describes weight-bearing exercise, meaning exercise where your feet and legs support your weight, as particularly important for bone density. The same page states plainly that swimming and cycling are not weight-bearing exercise. That is not a criticism of the bike. It is a description of what it does: it carries you.

What has actually been measured

A systematic review published in BMC Medicine in 2012 went through the literature on bone mass and bone metabolism in cyclists up to April 2012. Thirty-one studies of several kinds met the inclusion criteria: descriptive, cross-sectional, longitudinal and interventional.

The picture was not entirely uniform, as the authors say themselves. The material was heterogeneous in terms of sex, age, comparison group and which form of cycling was practised. But one pattern ran through it: adult road cyclists in regular training had low bone mineral density in key regions, with the lumbar spine as the example the review highlights. The conclusion was put plainly: road cycling does not appear to confer any significant osteogenic benefit.

Two further findings in the same review are as valuable as the headline result. The first is that other forms of cycling, mountain biking for instance, or cycling combined with other sports, appeared to be associated with better bone density. The second is an exclusion: the differences could not be explained by dietary patterns or endocrine factors in the available material. The authors' own hypothesis is about position and time instead. The hours are spent in a posture where the bike supports the body weight, and at competitive level they are followed by enforced recovery spent sitting or lying down.

What that does not mean for you if you ride to work

This is the point where health journalism usually goes off the rails, so let us take it slowly.

The material in the review comes from cyclists with high training volumes, in several cases competitive riders. There is nothing in that evidence saying a twenty-minute ride to work damages your skeleton. The finding is not that cycling breaks bone down. The finding is that cycling does not build bone, that it is neutral where other activities are positive. And the reason it does not build bone, that cycling is not weight-bearing, is also what makes it gentle on a sore knee. If you want weight-bearing cardio without the impact of running, walking with weight is an option, but the bone research is thinner than its reputation. The guide to rucking goes through it.

For someone who rides a bit and trains a bit, that means something very simple: your cycling does not count as your bone loading. It counts as your cardio. Those two accounts have to be filled separately.

The counterweight

The NHS guideline for adults aged 19 to 64 asks for strengthening activities that work all the major muscle groups on at least 2 days a week, alongside the aerobic minutes, and the WHO recommendation says the same. The NHS osteoporosis advice adds that weight-bearing and resistance exercise are particularly important for bone density. Those recommendations point the same way, and they already state the dose you need.

The question of which training actually raises bone density in people who already do low-impact sports is, on the other hand, still poorly understood. A scoping review in BMC Musculoskeletal Disorders in 2025 screened 2,528 studies and found five that met the criteria, in populations ranging from adolescent swimmers to elite road cyclists. The approaches showing promising results were resistance training, plyometric exercises, whole-body vibration, and jumping exercise combined with collagen supplementation. The authors' own summary is nevertheless that the evidence is limited: few studies, varying designs, and inconsistent reporting of what the training actually consisted of.

In practice that means you should not wait for a perfect protocol. Strength training is what both the official guidance and the thin research point towards. If raising bone density specifically is the goal, the methods that have been tested point towards loading that the skeleton can feel: resistance training, jumping and plyometrics. The habit itself can still be built at home without equipment: see strength training at home, which also covers what the research says about heavy loading. What is specific to you as a cyclist is that the sessions have to include legs and hips, not just upper body. That is where the gap sits.

How much cycling actually builds fitness

Cycling counts fully towards the official recommendations. The NHS guideline for adults aged 19 to 64 is at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity, and the WHO puts the range at 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity a week. The NHS lists riding a bike as an example of moderate activity, and riding fast or on hills as vigorous.

The line between the two is easier to feel than to calculate. The NHS describes moderate intensity as the level where you can still talk, but not sing.

The most common mistake among people who ride a lot is not too little time. It is that all of the time sits at the same middling pace, hard enough to tire you out but not hard enough to move anything. The principle behind how you distribute intensity is the same on a bike as it is when you run, and it is worked through in the guide to zone 2.

The bike as a detour when running is off the table

There is one use of a bike that is badly underrated, and that is as a fallback.

With problems like shin splints or Achilles tendinopathy, it is usually the impacts that are the problem rather than the endurance work itself. The bike removes the impacts and carries your body weight. That is also what 1177, Sweden's national health information service, advises for shin problems: rest from the activity that caused them, and in the meantime choose something that loads the lower legs less, such as cycling or swimming.

But the bike is not the universal answer to every running injury. For runner's knee, 1177 lists cycling among the possible triggers of that particular problem, and swimming or walking is usually the better substitute. So the rule is not that cycling replaces running. It is that cycling replaces the impacts.

That matters more than most people think, because fitness falls faster than strength does during a break. How fast, and what is enough to slow the fall, is covered in the guide to how fast you lose fitness. The point here is that you rarely have to choose between running and not training at all. There is a third option, and it is in the shed.

Two caveats apply, though. Cycling is not treatment for an injury, it is a way to keep training while the injury is being looked after. And if pedalling hurts, or the pain lingers afterwards, that is a reason to have a clinician or a physiotherapist look at it rather than to solve it on your own.

Four mistakes that cost the most

1. Letting the bike replace strength work. This is the expensive one, and it is what the whole page is about. Cycling pays into the cardio account. It pays into neither the muscle account nor the bone account. After 40 those two are not optional extras, they are what decides how your body works in twenty years.

2. Believing that heavy legs mean the strength session is covered. Tired is not the same as loaded. What you feel after a long ride comes largely from the volume of work, not from the muscle having received a heavy signal. It is in fact the same property that makes cycling a good partner for strength training: it takes little from your legs. The flip side is that it does not give them much either.

3. Riding everything at one pace. See the table above. If every ride lands at the same half-hard level, you get the wear of a hard session without either the recovery of an easy one or the development of a hard one.

4. Always taking the smooth road. This is the least certain suggestion on the page, so it comes with a caveat. The 2012 review noted that other forms of cycling, mountain biking for example, or cycling combined with other sports, appeared to be associated with better bone density. That is an observational finding rather than a demonstrated cause. But if you are choosing a route anyway, there is nothing wrong with letting some of your riding go off-road or uphill.

What the week looks like in practice

The detailed scheduling of strength alongside endurance, meaning the spacing between sessions and the order within a session, lives in the guide to strength training and running. If cycling is your main endurance work, three rules will do.

• Two strength sessions a week is the floor, not the ceiling. They have to include legs and hips. Muscle and bone are the two accounts cycling does not pay into.
• Let the cycling be cycling. It does not need to be arranged around your strength training the way running sometimes does. That is the whole point of this combination.
• Protect the strength session first when the week shrinks. If you ride to work, you already have a base of endurance work that stays in place even in a bad week. With that base covered, the strength session is the exposed one, because it is the only session that pays into the accounts cycling leaves open.

If you ride some days and are thinking about running on others: run commuting is the same idea with a different loading profile, and the two mix well.

Who should be careful

The recommendations on this page are for adults who are broadly healthy. The NHS advises speaking to your GP first if you have not exercised for some time, or if you have medical conditions or concerns, and making sure the activity and its intensity suit your fitness.

Contact a clinician if you get chest pain or pressure in the chest during exertion, an irregular heartbeat, breathlessness that is out of proportion to how hard you are working, or if you faint or feel dizzy while training. If you have known heart disease, high blood pressure that has not been investigated, or a current injury, involve a clinician in the plan before you increase anything.

Frequently asked questions

Can you cycle and lift on the same day?

Yes, and it is the pairing with the least evidence against it. In the 2012 meta-analysis of 21 studies, it was strength training combined with running that produced statistically significant losses in both muscle growth and strength. The same analysis did not find that effect when the endurance work was cycling. If you want to give your body the best conditions anyway, put a few hours between the two sessions rather than running them back to back. When that is not possible, the order matters far less than whether the session happens at all.

Is cycling bad for your bones?

No, but it does not build them either. A systematic review in BMC Medicine in 2012 went through 31 studies and concluded that road cycling does not appear to confer any significant benefit for bone building. Adult road cyclists in regular training had low bone mineral density in key regions, the lumbar spine among them. Two things decide how you should read that. The material comes from cyclists with high training volumes, not from people who ride to work. And the conclusion is that cycling does not do the job, not that it damages anything. The loading your skeleton needs simply has to come from somewhere else.

Is cycling enough on its own after 40?

Not as a complete setup. Cycling covers the aerobic side comfortably. The NHS guideline for adults aged 19 to 64 is at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity, and the WHO sets the range at 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity a week. The NHS lists riding a bike as moderate, or vigorous when it is fast or on hills. But the same guideline also asks for strengthening activities that work all the major muscle groups on at least 2 days a week, and the NHS osteoporosis advice adds that weight-bearing and resistance exercise are particularly important for bone density, while swimming and cycling are not weight-bearing. Cycling fills the first account and leaves the other two open.

Can I cycle instead of running while I am injured?

Often yes, because the bike carries your body weight and removes the impacts. That is why it works as a detour around many loading problems in the lower leg. Runner's knee is an exception: 1177 lists cycling among the possible triggers of that particular problem, so swimming or walking is usually the better substitute. It is not medical advice for your particular injury, though. If you cannot pedal without pain, or the pain lingers afterwards, that is a reason to have a physiotherapist or your GP look at it rather than to switch training mode on your own. The value of cycling here is mainly that it keeps your engine running while running hurts.

Do heavy legs after a ride mean the strength session is covered?

No. Tired is not the same as loaded. Pedalling is almost entirely shortening work: the muscles contract and push the crank around. What they largely do not do is brake your body the way they do in every running stride and in every controlled lowering of a weight. Heavy thighs after a long ride come mostly from the sheer volume of work. That tells you nothing about whether the muscle got the heavy signal it needs to get stronger, and nothing at all about your skeleton.

How much strength training do I need if I cycle a lot?

Two sessions a week covering all the major muscle groups is the level both the NHS and the WHO set out, and it is also the level that is realistic alongside cycling. You do not need a gym to get there. What matters for this particular question is that the sessions load your legs and hips, because that is where cycling leaves its gap. If bone health is your main concern, or you have broken a bone after the age of 50, talk to your GP about what is right for you rather than guessing.

Evidence base: the meta-analysis of concurrent endurance and resistance training in the Journal of Strength and Conditioning Research 2012 (21 studies, 422 effect sizes, PMID 22002517), the systematic review of cycling and bone health in BMC Medicine 2012 (31 studies, literature up to April 2012, PMID 23256921), the scoping review of exercise interventions for bone mineral density in low-impact sports in BMC Musculoskeletal Disorders 2025 (2,528 studies screened, 5 included, PMID 39833826), NHS physical activity guidelines for adults aged 19 to 64, NHS guidance on preventing osteoporosis, and the WHO recommendations on physical activity.