Rucking: Walking with Weight as Endurance Training

Rucking means walking briskly with a pack on your back, carrying between ten and twenty percent of your body weight. It sounds like military culture, but aerobically it is one of the most efficient training methods there is — calorie burn is one and a half to two times that of a normal walk, heart rate climbs into the aerobic band, and impact loading stays well below running. For endurance athletes rucking is therefore not a gimmick but a tool: a second session, winter volume, a bridge through injury.

What rucking is — and where it comes from

Rucking is the English term for covering distance with a pack and a defined load, originally from military training where marching with kit is daily craft: twelve to twenty kilograms, four to six kilometres per hour, several hours at a time. In the United States it has grown into a sport of its own, with standardised distances, weight classes and events over five, ten and twenty kilometres.

For everyday training the origin is irrelevant; the mechanics are what matter. You walk, which means there is no flight phase. That is exactly the appeal for runners. Running produces peak forces of two to three times body weight per stride on tendons, cartilage and bone. Rucking spreads the same or a higher metabolic load across a movement without impact — so you can build aerobic capacity and leg strength while sensitive structures rest.

Why walking with weight works physiologically

• Heart rate: With ten to fifteen kilograms at a brisk pace you land at 60 to 75 percent of maximum heart rate — the band where aerobic base develops, without having to force it.
• Calorie burn: At 80 kilograms body weight and a 12-kilogram pack you burn roughly 400 to 550 kilocalories per hour depending on pace and terrain. A brisk walk sits at 250 to 300.
• Muscular endurance: The load forces trunk, hip extensors and calves into continuous stabilising work. That is not maximal strength training but exactly the kind of work that counts on long climbs in the second half of a race.
• Bone and tendon: Added weight creates tensile and compressive stimulus on the skeleton without the repeated impacts of running. For bone health that is a welcome signal.
• Thermoregulation: A pack means an extra layer on your back. In summer that is an unintended heat stimulus — in winter it is an advantage.

How much weight is right?

The rule of thumb is ten percent of body weight to start. At 75 kilograms that is 7.5 kilograms, at 90 kilograms it is nine. That load is enough to challenge the cardiovascular system noticeably without overloading posture and joints. After four to six weeks without complaints you can move to fifteen percent; long term, twenty percent is defensible for trained athletes.

Above 25 percent it becomes uneconomical: the upper body starts compensating, stride length drops, recovery time rises disproportionately — without any further gain in aerobic stimulus. For endurance athletes load is not the lever anyway, duration is. Better 60 minutes with 10 kilograms than 30 minutes with 20.

Distribution in the pack matters too: heavy items belong high and close to the body, right against the spine. A loose pack with weight at the bottom pulls you backwards, you instinctively lean forward, and the lower back works against a lever it does not need.

Pace, duration and heart rate

The goal is brisk walking — four to six kilometres per hour, at which you can still speak in full sentences. That sounds easy but is surprisingly demanding on the first attempt with a pack: many drift unnoticed to 75 to 85 percent of maximum heart rate, i.e. into threshold territory, and then wonder why they are tired the next day.

• Beginners: 30 to 40 minutes, flat, no breaks, two sessions per week.
• Build: 50 to 70 minutes, hilly terrain, load constant.
• Advanced: 90 to 120 minutes, long ruck marches as a standalone endurance session — ideal as a substitute for a second long run when the legs need a break from impact.

Control works as in heart rate training, via pulse or the talk test. If heart rate rises by more than ten beats at the same load and pace, that is a fatigue signal — or a sign of poor sleep, heat or an oncoming illness.

Gear: what actually matters

• Pack: A pack with a padded, rigid hip belt carries the load on the pelvis, not the shoulders. A normal daypack with a floppy back panel works for 30 minutes; for longer sessions it becomes a postural problem.
• Weight: Water bottles, sandbags, weight plates or a litre of milk — mechanically irrelevant as long as the load sits immobile. Water has the advantage that you can drink it and reduce weight along the way.
• Shoes: Cushioned running shoes or light hiking boots. Under load you need more stability than on an easy run; barefoot shoes are the wrong choice here.
• Clothing: The pack rubs at shoulders and hip bones. Nothing with coarse seams at the contact points, no cotton T-shirt on longer sessions.

Spending several hundred euros on dedicated rucking packs is not necessary to start. A mid-sized trekking pack with a good hip belt and two water crates serve the same training purpose.

Technique: the four points that count

• Walk upright. Do not lean forward, even when the load pulls. Eyes twenty metres ahead, chest open, shoulders low.
• Hold stride length. Under load we tend to take shorter, hurried steps. Deliberately go slightly longer but evenly — that spares the calves and holds the pace.
• Active arms. Do not let them hang, swing them. On climbs a strong arm drive helps, exactly as in hill training.
• Brace the trunk. The pack is a lever on the upper body. Anyone who lightly braces the abdomen and pulls the shoulder blades down and back prevents the forward tip and relieves the lower back.

Rucking in the training plan: where it belongs

Rucking does not compete with running, it complements it with a clear role. Three sensible placements:

• As a second session on the long run day: Not attached to the long run itself but on the afternoon after it — the muscles then work already fatigued and the stimulus resembles a back-to-back run, only without additional impact loading.
• As winter volume: When ice, darkness and cold degrade running quality, a 60-minute ruck replaces an easy aerobic run one to one.
• As an injury bridge: With shin splints, plantar fasciitis or knee problems, rucking maintains endurance while running is paused. That is the most valuable practical application — provided the load is low and symptoms do not worsen.

In load management, one hour of rucking counts roughly like 35 to 45 minutes of easy running. That is an estimate, not a measurement: anyone tracking TSS precisely should apply a factor of about 0.5 to 0.6 per rucking hour relative to a running hour. Anyone using rucking permanently as a second session should steer the rest of the week deliberately — the 16-week marathon training plan shows how phases and volumes are structured.

What rucking does not deliver

Two limits have to be named clearly, otherwise a good tool turns into a substitute belief. First: walking does not train the running-specific movement. The stretch-shortening cycle, elastic energy storage in the Achilles tendon and arch of the foot, neuromuscular coordination at high cadence — all of that requires running. Anyone using rucking as a complete running substitute loses running economy within four to six weeks.

Second: rucking is not strength training. The loads are too low for maximal force development; for strength training for runners you need squats, deadlifts and single-leg variants at considerably higher intensity. Rucking delivers muscular endurance, not maximal strength.

Common mistakes

• Too heavy too soon. The classic start with 20 kilograms leads to shoulder and neck tension and irritated knees. Two weeks at ten percent of body weight is not lost time.
• Too fast on pace. Anyone rucking as if it were a race loses the aerobic character. Rucking should feel like "brisk but relaxed".
• Pack without a hip belt. That leaves the entire load hanging from the shoulders — neck pain is pre-programmed.
• Rucking as a running replacement. See above: replacing half your running volume costs pace hardness and economy.
• Rucking right before a quality session. A 90-minute ruck the day before intervals costs leg freshness. Hard sessions belong at least 48 hours afterwards.
• Never without water. With a pack you sweat considerably more than when running at the same perceived effort. For sessions over 60 minutes fluid intake belongs in the plan — see hydration for runners.

Example: a rucking week for a marathon runner

• Monday: Rest day.
• Tuesday: Intervals 5 × 1,000 m at 10K pace.
• Wednesday: 45 minutes rucking, 10 kg, flat, heart rate below 70 percent.
• Thursday: 60 minutes easy running.
• Friday: Rest day or 20 minutes of mobility.
• Saturday: 60 minutes rucking, 12 kg, hilly — replacing the second easy run.
• Sunday: Long run 28 km easy.

That is two rucking sessions totalling 105 minutes and equivalent to roughly 60 to 70 running minutes in the aerobic band — without a single additional impact on tendons and cartilage. That ratio is exactly what makes rucking interesting for endurance athletes.

How Peakora handles rucking

In Peakora, rucking runs alongside the running plan as a supplementary session: you can log it as an aerobic alternative when legs or weather demand a break from running, and the engine factors it into your CTL/ATL/TSB history at a reduced load factor. That keeps the fitness curve honest even in a week where you walk more than you run. Structured running work, threshold stimuli and race pace remain the plan's job.

Frequently asked questions about rucking