When you climb, the aerobic and anaerobic systems work at the same time rather than taking turns, and each time you let go to move, blood flow brings oxygen into the forearm and carries metabolites away. As Lattice puts it, the aerobic system needs volume and the anaerobic system needs intensity; climbing until you're pumped out lands in between and trains neither. Below critical force you can keep climbing; above it, the clock starts.
Foot problems are common in climbers: one on-site examination of 144 climbers found foot pathology in 86%, nail problems most of all. Bunions are clearly more common in high-level climbers, but these are cross-sectional studies and can't show the shoes caused them. Studies disagree on whether downsizing is linked to pain; a bouldering study found more serious injuries among people wearing heavily downturned shoes. The practical answer is two pairs: a comfortable pair near your street size for most climbing, and a tight pair only for hard attempts.
Flexibility affects climbing performance, but less than strength and endurance: in a 2000 study it explained only 1.8% of the variance in performance, and the authors of the IRCRA test battery suggest it may be a 'threshold' quality where enough is enough. General tests such as the sit-and-reach barely relate to climbing ability; climbing-specific hip tests do. A 2023 systematic review found no association between stretching and overuse injury, so train mobility to put your feet where you want them, not to prevent injury.
Start footwork with three things: keep your eyes on the foot until it takes weight, place the front of the shoe precisely the first time, and make no noise. Warm up on routes two grades easier with quiet-feet and sticky-feet drills. 'Climb with your feet, not your arms' roughly holds on vertical walls; the steeper the wall, the more weight shifts to your hands, so on overhangs the cue becomes 'keep your feet on the wall'.
Tell the three grips apart by two joints. In an open hand the fingers are only slightly bent. In a half crimp the middle joint bends to about 90°, the fingertip joint does not bend backwards, and the thumb stays off. In a full crimp the fingertip joint bends backwards and the thumb wraps over the index finger. The full crimp puts the most load on the A2 pulley; one biomechanical model puts it at 36 times the open-hand load. So default to an open hand or half crimp, and full crimp only when nothing else works. Hooper's Beta's 'open crimp' is a half crimp, not an open hand.
There is no dedicated research on home training; this post collects coaching advice from Lattice, Power Company, the BMC and Hooper's Beta. The minimum kit is a doorframe pull-up bar plus a hangboard or lifting block. Until you're experienced, keep hangboard sessions under 20 minutes and take weight off with your feet on a chair; use the bar for pull-ups and lock-offs and the floor for press-ups and core. Home training can maintain finger strength, but improving still means getting back on the wall.
Where climbers get hurt depends on where the data comes from: in a sports-medicine clinic more than half of injuries are fingers; in US emergency-department data half are lower-limb injuries, mostly fractures from falls. A head strike in a fall, new numbness or weakness, a deformed limb or a crack at the moment of injury means call 119 or go to the ED. A finger that pops and then swells, or finger pain in anyone under 18, needs a doctor soon. In Taiwan a physiotherapist treating an injury must work from a doctor's diagnosis or referral, so see the doctor first.
A German multicentre study of 77 acute climbing knee injuries found the heel hook was the most common mechanism, at 40.3%. In a separate case series of 17 heel hook injuries, every patient had sudden pain at the back of the knee, thigh, or pelvis and was limping; 15 did well with conservative treatment, but 11 had come for a second opinion. A pop followed by limping, a dent plus bruising, or a knee that catches or locks all need assessment by a doctor or physiotherapist.
On the same route, novices put less weight through their feet yet use more oxygen and have higher heart rates. When you plateau, run a quiet-feet test on a route two grades below your limit: if easy routes still pump you out, the problem is usually movement. The series follows the federations' teaching order: footwork, balance, turning, holds, dynamic moves, bouldering problem solving, resting and route reading, wall angles, cracks.
Elite climbers are lean on average, but in Lattice's data BMI showed no significant correlation with grade, and they observed that climbers who stay in a long-term calorie deficit struggle to gain finger strength. Several studies find climbers under-eat: in one study of 25 advanced to elite climbers, 28% had low energy availability. Watch three groups of RED-S warning signs: menstrual changes, repeated injury or illness, and training that stops paying off. For recovery, Eva López recommends 48–72 hours between hangboard sessions. If you suspect RED-S, get assessed by a doctor or registered dietitian.
Periodization is simply organising training over time. With three sessions a week, start with three rules: in each session do the strongest, hardest work first and the low-intensity work last; leave 48–72 hours between finger-heavy sessions; when you add something new, take something else out. Then group 3–4 weeks into a mesocycle and make the last week a deload, cutting total load by 40–60% rather than resting completely. Anderson's linear model trains one quality at a time; Bechtel argues no quality should be dropped for long. No research in climbing has shown which is better.
In specialist clinic data, the shoulder is the second most common injury site after the fingers. Impingement is common in climbing but needs to be told apart from a rotator cuff tear: pain when raising the arm with strength intact looks more like impingement; clear weakness in external rotation, or an arm you can't lift after an injury, means seeing a doctor. In 50 elite climbers with no shoulder pain, 80% had intra-articular findings on MRI, so a finding on a scan isn't the same as an injury. A randomised trial of 84 student climbers found that closed-chain plus eccentric strength training reduced shoulder injuries.
In the 2025 German and Austrian climbing-gym statistics, more than half of serious rope-climbing accidents were spinal injuries from ground falls, and many happened while lowering, not while climbing. Low back pain is common in young competitive climbers but mostly mild and doesn't stop training. "Belayer's neck" is not an official diagnosis, and belay glasses haven't been tested in a study. The "climber's hunch" rests on one cross-sectional study that found more thoracic curvature in high-level male climbers, all of whom had no symptoms and whose pain was never measured.
Beyond your fingers, pulling strength in the shoulders and back also tracks grade: in a 2025 National Taiwan University thesis on 25 advanced men, only weighted pull-up relative to body weight predicted grade. Train bodyweight pull-ups until you can do 10; Lattice sees diminishing returns above 165% of body weight (135% for women). Campus thresholds differ: Gresham wants two years of bouldering and hangboarding and about V6/7 before going feet-off; the UIAA says 8–10 years of climbing. No feet-off or dynamic campusing under 18 is advice shared by the BMC and the UIAA.
Most coaches tell climbers about a year in to fix technique first, but not all of them: Eva López wants more than 2 years of systematic climbing and a 15-second hang on a 25 mm edge before hangboarding, while Lattice's data shows finger strength is the single best predictor of grade. Rule out technique with a quiet-feet test two grades below your limit, then check whether you freeze on lead, and only then test finger strength and pull-ups.
A barn door happens when your hand and foot on the same side are your only contact, and your body swings open around that line. Fix it with diagonal support (push on your right foot, hold with your left hand) or by swinging your free leg out as a flag. With one foothold, backstep or flag; with two footholds at similar height on either side, drop knee. In one knee-injury study, drop knees accounted for 16.9% of acute knee injury mechanisms, so skip them if your knees are hurt.
The steeper the wall, the more weight moves from your feet to your hands, and the research agrees on that. So on slab, press your weight onto your feet and smear with heels low; on vertical, follow the fundamentals; on overhangs, lesson one is keeping your feet on; on roofs, treat heel hooks and toe hooks as a third and fourth hand. "Straight arms mean resting" is only half right: it spares the biceps, but your fingers are still working.
In Quarmby's 2023 systematic review, four studies found no protective effect of warming up against overuse injury; among randomised trials of upper-body warm-ups, not one measured injury prevention. The value of a warm-up is performance: a Kaohsiung crossover trial found 10-minute warm-ups increased upper-limb mobility and elbow and shoulder strength, but not finger flexor strength. A practical routine is general warm-up, shoulders, easy climbing, finger efforts in the grips you'll use, then technical and mental preparation, about 15 minutes.
Crack climbing is not gripping and pulling; you insert a body part and expand it. Climb straight cracks thumbs-up; thumbs-down is usually the most secure for resting or placing gear; on slanting cracks, top hand thumbs-down and bottom hand thumbs-up, shuffling without crossing. Long Dong's rock is described two ways: Taiwanese sources say 四稜 sandstone, Mountain Project says quartz-rich metaconglomerate, and both call it coarse and high-friction, so tape up. Taiwanese trad courses mostly teach protection; jamming needs separate practice.
With signal, call 119 first: the dispatcher can send a location text and get your coordinates. Only call 112 (then press 9) when 119 won't connect; 112 is voice-only, so you read out coordinates yourself, and since 3G shut down only VoLTE phones can dial it. In one 2026 Long Dong fall it took about an hour from the call to paramedics reaching the patient, so how people at the scene split the work matters: one calls and stays on the line, one guides rescuers from the entrance, others fetch the emergency kits TOCC keeps at the crag. The most useful piece of kit is training: TWMA's WFA is two days, 16 hours, and the Taiwan Society of Emergency Medicine runs a wilderness life support course.