If you look at the data from alpine rescue services across Europe — the Austrian Bergrettung, the Swiss REGA, the French PGHM, the Italian CNSAS — the same injuries appear repeatedly. Not exotic altitude illnesses or dramatic rockfall events, but ankle sprains, knee overuse injuries, blisters that became infected, fatigue-related falls in the last hour of a long descent, and hypothermia that developed because a hiker stayed wet for too long. These are the injuries that actually end hiking days, and they share a consistent set of causes.

Most of them are preventable. Not in the abstract, vague sense of “be careful” — but specifically, with identifiable interventions before and during the walk that reduce their probability dramatically.

Ankle Sprains: Injury #1 by Frequency

Ankle sprains are the most common trail injury by a significant margin. They occur when the foot rolls inward (inversion) or outward (eversion) beyond the range the ankle ligaments can accommodate. The standard explanation is “uneven terrain” — which is true but incomplete. The full causal chain:

• Fatigue is the primary contributor. Ankle sprains cluster in the final 20–30% of a long descent, when proprioceptive function (the body’s unconscious position sense) is degraded by muscle fatigue. A fresh ankle navigates an uneven surface; a tired ankle rolls on it.
• Boot sole rigidity matters. A stiff-soled mountain boot reduces ankle roll risk on uneven terrain because the load is distributed across the boot platform rather than concentrated at the ankle joint. Trail runners and soft-soled shoes allow more ankle movement — desirable for trail running technique, hazardous for tired descents on rocky terrain.
• Attention drops before the ankle does. Most sprains on familiar routes occur when a hiker thinks they know the terrain and stops watching their foot placement. Technical terrain deserves full attention regardless of familiarity.

Prevention: trekking poles on descents (reduce ankle load by 20–25%); proprioceptive training (single-leg balance, balance board work in the weeks before a demanding trek); realistic pacing that keeps energy reserves for the descent; attention discipline maintained to the trailhead, not just the summit.

Knee Pain: The Descent’s Tax

Patellofemoral syndrome (pain under the kneecap on descent), IT band syndrome (pain on the outer knee), and acute medial collateral ligament strain from twisting falls together represent the second most common category of hiking injury. They share a common mechanism: the knee absorbs disproportionate force during descent, and inadequately conditioned supporting structures fail under cumulative load.

The specific physiological problem on descent is eccentric quadriceps contraction — the thigh muscles are lengthening under load rather than shortening. This produces significantly more muscle damage per unit of effort than climbing, which is why descents hurt more than ascents despite feeling easier aerobically.

Prevention: step-down exercises (the most specific prehabilitation for knee descent load), trekking poles (transfer up to 25% of knee load to the arms on descent), anti-chafe and anti-inflammatory preparation for multi-day trekking, and realistic daily distance management. A day that finishes with significant knee pain is a day that has exceeded the adaptation capacity of that knee — reduce the next day’s distance before the pain becomes structural damage.

Back Pain: The Pack Problem

Lower back pain on multi-day treks is almost universally caused by one of three factors: pack too heavy, pack poorly fitted, or pre-existing lumbar weakness that multi-hour loaded walking reveals. The lumbar spine is not designed for sustained anterior loading (the pack pulling the upper body forward); it is designed for upright posture. A pack that doesn’t transfer weight to the hip belt forces the lumbar extensors to work continuously to maintain posture — they fatigue, they spasm, the walk ends early.

Immediate field management: pack-off breaks every 60–90 minutes; cat-cow mobility movement at breaks; hip belt readjustment so 70–80% of weight is on the hips, not the shoulders; ibuprofen for acute spasm if no contraindications; forward-lean walking poles to redistribute load.

Prevention: hip hinge strength training (Romanian deadlifts, good mornings) in the 8 weeks before a demanding trek; realistic pack weight reduction (target under 10% of body weight for daily load, under 15% for multi-day); professional pack fitting before purchase.

Sun and Heat Injuries

Sunburn

At 2,000m altitude, UV intensity is approximately 20% higher than at sea level — at 4,000m, 40% higher. Snow reflects 80% of UV radiation. A hiker on a high-altitude snowfield is receiving UV from above and below simultaneously. Sunburn at altitude progresses faster and is more severe than at sea level. Apply SPF 50+ to all exposed skin every 90 minutes, including under the chin (snow reflection) and the tops of the ears. UV-protective sunglasses (category 3 minimum; category 4 for glacier terrain) prevent photokeratitis (snow blindness — a painful UV burn of the cornea).

Heat exhaustion

Heat exhaustion (not yet heat stroke) presents as: heavy sweating, pale cool clammy skin, weakness, nausea, headache, dizziness. It is caused by fluid and electrolyte depletion in hot conditions. Treatment: move to shade immediately; lie down with legs elevated; replace fluids with electrolyte solution (not plain water alone, which can cause hyponatraemia by diluting remaining electrolytes); cool the skin with wet clothing; rest until fully recovered before continuing.

Heat stroke (medical emergency)

Heat stroke differs from heat exhaustion in one key sign: the skin is hot and dry (sweating has stopped), and the person is confused or losing consciousness. Core temperature is above 40°C. This is a life-threatening emergency requiring immediate cooling (wet the person, fan them, apply ice to armpits, groin and neck) and emergency evacuation. Do not give fluids to an unconscious person.

Falls: The Injury Category That Kills

Falls are the leading cause of mountain fatality and the leading cause of serious (evacuation-requiring) injury. Unlike most other hiking injuries, falls cannot be entirely prevented — terrain is unpredictable and human attention has limits. But the circumstances that make falls likely are consistent and reducible:

• Fatigue: more than 60% of hiking falls occur in the final third of a descent, when fatigue is highest and attention is lowest. Reduce pace before you feel tired — by the time the effort registers, the risk is already elevated.
• Wet conditions: wet rock, wet grass, wet roots and wet scree all dramatically reduce grip. In wet conditions, reduce pace, test surfaces before committing weight and use trekking poles for additional contact points.
• Inappropriate footwear: smooth-soled shoes on loose terrain, sandals on rock, trail shoes on steep wet grass — footwear mismatch with terrain is a consistent fall factor. Know what your soles grip and where they don’t before the terrain demands it.
• Pack weight shifting: a heavy pack shifts the centre of gravity rearward, making recovery from a stumble on descent significantly harder. This is another argument for realistic pack weight, not just for comfort but for fall prevention.

The Injury That Precedes All Others: Fatigue

Every injury category above — ankle sprains, knee pain, falls, heat exhaustion — has fatigue as a major contributing factor. Fatigue degrades proprioception, attention, decision-making and physical capacity simultaneously. The experienced hiker’s primary injury prevention tool is not a kit item; it is pace management.

Leave earlier. Eat and drink before you feel hungry or thirsty. Add a rest stop 30 minutes before your schedule suggests one. Start the descent with reserves rather than reserves spent. Mountain safety is not primarily reactive — it is the discipline of staying well inside your physical limits on every walk, building the margin that absorbs the unexpected when it arrives.