Prepare the System Not Just the Salt Strength Training and Cramp Prevention for Runners
Cramp in a marathon can feel like it comes from nowhere. One minute the pace is under control, the next the calf, hamstring or quad locks up and the whole race changes.
The usual response is simple: take more salt, drink more, blame electrolytes. That may be part of the picture for some runners, but recent research suggests it is not the whole story.
A study published in the Journal of Strength and Conditioning Research, titled Muscle Cramping in the Marathon: Dehydration and Electrolyte Depletion vs. Muscle Damage by Ignacio Martínez-Navarro and colleagues, adds useful weight to a point many coaches see in practice: marathon cramp often looks less like a pure hydration problem and more like a fatigue, muscle damage and preparation problem.
That matters whether someone is trying to break 5 hours, run a club championship, or compete at national level. The pace changes, but the principle stays the same. The body has to be prepared for the demands of the event.
What the marathon cramp study looked at
The study compared two common explanations for exercise-associated muscle cramping in the marathon:
dehydration and electrolyte depletion
muscle damage and fatigue
The traditional view is that runners cramp because they lose too much fluid or too much sodium. That is why many runners immediately reach for salt tablets, sports drinks or extra water when cramp becomes an issue.
This paper challenges the idea that dehydration and electrolyte loss are always the main cause. The findings point more strongly towards muscle damage as a key factor in marathon cramping.
That does not mean hydration is irrelevant. Fluid and sodium intake still matter for performance, health and comfort, especially in warm conditions. A poor fuelling or hydration plan can still ruin a marathon. But the important point is this:
If a runner cramps late in a marathon, the answer is not always “take more salt”. It may be “prepare the muscles better for the load”.
That is a big difference.
For coaching, this is useful because it pushes us away from single-cause thinking. Cramp is rarely solved by one product, one gel, one electrolyte drink or one race-day trick. More often, it reflects how well the runner’s body has been conditioned to tolerate repeated impact, long-duration fatigue and race-specific intensity.
Why muscle damage matters in the marathon
A marathon is not just a long aerobic event. It is also a long eccentric loading event.
Every stride involves the muscles absorbing force. The quads help control landing. The calves and Achilles manage stiffness and propulsion. The hamstrings and glutes help stabilise and drive the leg through. Over thousands of steps, this creates fatigue and micro-damage.
For a well-prepared runner, the body can manage that load for longer. For an underprepared runner, the system starts to lose control. Stride mechanics change. Ground contact gets heavier. Muscles that were coping at mile 10 may begin to struggle badly at mile 20.
This is where cramp may appear.
From a coaching point of view, cramp often shows up when there is a gap between the race demand and the runner’s preparation. That gap can come from several places:
not enough long runs
not enough marathon-pace work
too little strength training
poor downhill conditioning
racing harder than training supports
a sudden jump in volume or intensity
inadequate recovery during the build-up
limited experience running on tired legs
For an amateur runner, that might mean the longest run was far too short or too close to race day. For a club runner, it might mean fitness was strong but the legs were not conditioned to hold form at marathon pace. For a national-level runner, the issue may be subtler, such as small weaknesses in calf capacity, hip control, hamstring endurance or tolerance to high-volume sessions.
The faster the runner, the higher the forces. The slower the runner, the longer the exposure. Both can cramp for different reasons.
Why strength and conditioning belongs in marathon preparation
Strength and conditioning is sometimes treated as an optional extra for runners. Something to do if there is time after the miles are done.
That is a mistake.
The marathon rewards aerobic fitness, but it also exposes weak links. Strength training helps build a body that can keep using that fitness when fatigue rises.
Good runner-specific strength work can improve:
calf and Achilles capacity
quad strength for repeated landing forces
hamstring resilience
glute strength and pelvic control
trunk stability under fatigue
single-leg balance and coordination
ability to hold form late in long runs and races
This does not mean runners need to train like bodybuilders. It means they need enough strength to meet the demands of their event.
For marathon runners, strength and conditioning should support running, not compete with it. The goal is not to be sore all week. The goal is to become more tolerant of the work.
A simple strength plan might include:
squats or split squats
Romanian deadlifts
step-ups
calf raises with straight and bent knees
hamstring bridge variations
side planks or carries
controlled hopping or low-level plyometrics when appropriate
The details should match the runner. A beginner does not need the same programme as a national-level runner. A runner with a history of Achilles pain needs different progressions from someone who cramps mainly in the hamstrings. But the principle remains the same: build the tissues before asking them to survive the race.
Cramp is often a preparation signal, not just a nutrition issue
Many runners only think about cramp in the final week before a race. At that point, options are limited. It is tempting to look for a quick fix.
Salt tablets are easy to buy. Strength capacity takes months to build.
That is why the salt answer is so attractive. It is simple, immediate and easy to control. But if the main issue is muscle damage and fatigue, then a last-minute supplement will not fix the underlying problem.
A runner can be well hydrated and still underprepared. A runner can take electrolytes and still cramp because the calves have never been conditioned to handle 42.2 km at that pace. A runner can nail the fuelling plan and still break down because the long runs, strength work and recovery were not enough.
This is where the recent research lines up with what many coaches see in real life.
The runners most at risk are often not lazy or careless. Many are fit. Many have trained hard. The problem is that their training has not prepared the whole system.
That system includes:
cardiovascular fitness
muscle endurance
tendon stiffness and tolerance
neuromuscular control
pacing judgement
heat tolerance
fuelling and hydration habits
recovery capacity
Cramp can sit at the intersection of all of these.
What this means for amateur runners
For newer and amateur marathon runners, the biggest win is often consistency.
Cramp risk may rise when the race is a much bigger demand than training has prepared the body for. That does not mean every runner needs huge mileage. It means the training should progress sensibly and include enough specific work.
Key priorities include:
Build the long run gradually
The long run conditions the legs as much as the lungs. It teaches the body to handle repeated impact, fuel use and fatigue. A rushed long-run build can leave the muscles underprepared.
Practise marathon pace
Many runners do easy long runs and hard short sessions, but very little work at target marathon rhythm. Marathon-pace running teaches the body the exact demand it will face on race day.
Add strength training early
Two short sessions per week can be enough for many runners. The work does not need to be complicated, but it does need to be progressive.
Respect recovery
Muscle damage is not only caused by race day. It builds during heavy training blocks. If recovery is poor, the body may arrive at the start line carrying more fatigue than expected.
Do not experiment on race day
Hydration and fuelling still matter. Practise them in long runs. Avoid making sodium, caffeine or fluid changes for the first time during the marathon.
What this means for club and national-level runners
Faster runners need the same foundations, but the margin for error is smaller.
Club and national-level runners often have excellent aerobic capacity. They may handle high mileage and demanding sessions. Yet cramp can still appear when race pace exceeds the musculoskeletal preparation.
For these runners, strength and conditioning should become more individual.
A coach may look at:
repeated calf capacity under load
hamstring strength at longer muscle lengths
hip and trunk control when tired
asymmetry between sides
ability to tolerate faster downhill running
changes in stride late in marathon-pace sessions
fatigue after key workouts
The aim is not to add random gym work. The aim is to identify the likely weak link and train it.
For example, a runner who repeatedly cramps in the calves late in marathons may need more than generic lower-body strength. They may need progressive calf loading, heavy soleus work, plyometric progressions, hill tolerance and better pacing discipline.
A runner who cramps in the hamstrings may need posterior-chain strength, trunk control, improved hip extension mechanics and better fatigue resistance at marathon pace.
At higher levels, small gaps matter. A slight weakness that never appears in a 10 km session may become obvious after 30 km of marathon racing.
A practical weekly strength template for runners
Strength training does not need to dominate the week. It needs to be placed well.
For many marathon runners, two sessions are a good starting point.
Session | Focus | Example work |
Session 1 | Heavier strength | Split squat, Romanian deadlift, calf raise, side plank |
Session 2 | Control and capacity | Step-up, single-leg bridge, bent-knee calf raise, low-level hops |
The loads, sets and exercises should fit the runner’s level. Early in a marathon block, strength work can be more developmental. Closer to race day, it may become lighter and more focused on maintenance.
The mistake is leaving it too late. Strength adaptations take time. Tendons, muscles and coordination do not change much in a final taper. The best cramp-prevention work often happens months before the race.
Hydration still matters, but it is not the whole answer
This research should not be read as permission to ignore hydration or electrolytes.
A poor drinking strategy can still affect performance. Hot conditions can increase strain. Heavy or salty sweaters may need a more careful sodium plan. Long races require a fuelling strategy that has been tested in training.
But the study adds to the case that cramping is not just about dehydration and electrolyte depletion. Runners still often reach for salt first, and this study does not strongly back that up as the main explanation.
The better approach is to treat hydration as one part of the plan, not the whole solution.
A complete marathon preparation plan should include:
progressive mileage
long runs that match the race goal
marathon-pace practice
strength and conditioning
sensible recovery
heat preparation when needed
tested fuelling and hydration
honest pacing
This is especially true for runners who cramp repeatedly. If the same issue appears in multiple races, the answer is probably not another random race-week fix. It is time to look at the training history, strength capacity and race demands together.
This article is for general information and coaching education. Runners with recurrent, severe or unusual cramping should seek advice from a qualified health professional.
My coaching take
My take is simple: prepare the system, not just the salt.
This study adds to the case that marathon cramping is not only about electrolytes and dehydration. Those things matter, but they are not always the main driver. Many runners reach for salt first, yet the research points more towards muscle damage and fatigue as major contributors.
From my coaching experience, cramp often appears when a runner is not fully prepared for the specific demands of the race. That may be an amateur runner whose long runs were not enough, a club runner who lacked strength endurance, or a national-level runner whose pace exposed a small physical weakness late in the race.
If cramping is the issue, the goal should be to prepare the neuromuscular and musculoskeletal systems for the event. That means a progressive plan, enough marathon-specific work, consistent strength training, sensible heat preparation, and a nutrition strategy that has already been practised.
Salt may help some runners in some conditions. But for many, the bigger answer is better preparation. Build the body that can handle the marathon, not just the bottle that gets carried through it.
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