Sport
CrossFit, and the functional fitness classes modelled on it, mix weightlifting, gymnastics and cardio into short, very hard workouts that change every day. The workouts can be scaled to anyone, and they do improve fitness, though the research is thin. Injury rates look like those in weightlifting and other gym sports, and injuries are more common in beginners, people training without a coach and people with old injuries.
This guide covers what the workouts ask of your body, the injuries that happen (shoulders, backs, knees and wrists), how to start without getting hurt, the rare but serious muscle breakdown called rhabdomyolysis, leaking and pelvic floors, and who should check with a GP first. There are two workouts with 3D demos: a beginner session in the shape of a class, and a warm-up and mobility routine. We're not connected with CrossFit or any brand, gym or governing body; we describe the method so you can train safely.
CrossFit's own description: every class is coached, with a warm-up, skill or strength work, the "Workout of the Day" and a cool-down, and "Every workout can be scaled". Researchers call the wider method high-intensity functional training (HIFT): multi-joint moves over varied durations, with or without rest.
Across 28 studies of 11,089 people, there were about 4 injuries per 1,000 hours of training, and 36% had been injured at some point, mostly shoulders, backs and knees. Olympic weightlifting runs at 2.4 to 3.3 injuries per 1,000 hours.
Being new, training without a coach watching, a previous injury and switching between scaled and full loads all went with more injuries. These are associations, mostly from surveys and short studies.
The one trial, a 10-week mobility and stability warm-up in 32 recreational athletes, found no difference. Prevention rests on coaching, steady scaling and building up gradually (our reading).
Of 523 people treated for CrossFit injuries at one US hospital over 6 years, 11 had rhabdomyolysis, a breakdown of muscle that can harm the kidneys, and most were beginners. Dark urine or very painful, weak muscles after a session need medical help the same day.
Across 13 surveys, 44.5% of women who do CrossFit reported leaking urine, often with jumping. In a trial, 16 weeks of daily pelvic floor training improved it for 64% of women, against 8% without it.
CrossFit calls itself "a global fitness brand with a community and a methodology of constantly varied functional movements performed at relative intensity", with "coached workouts that build strength, conditioning, and confidence at a level that is challenging but appropriate for you". A class starts with a warm-up to "Prepare your body, increase your heart rate, and practice the movements you will use in class", then skill or strength work, the workout of the day, "adapted to your ability, experience, and goals", and a cool-down.
High-intensity functional training "emphasizes functional, multi-joint movements that can be modified to any fitness level". Unlike high-intensity interval training (HIIT), with its fixed hard and easy bouts, it varies the exercises and durations, with or without rest. Gyms that aren't CrossFit affiliates run the same kind of class as functional fitness, cross training or HIFT.
Typical workouts combine Olympic weightlifting (the snatch and the clean and jerk), gymnastics moves (pull-ups, push-ups, handstands and sit-ups) and rowing, cycling or running, in a set time, along with squats, deadlifts, presses, kettlebell swings, box jumps, wall balls and burpees. Workouts are done for time, as many rounds as possible (AMRAP), or every minute on the minute (EMOM). Our EMOM and AMRAP guide explains the formats, and our lift guides teach the main lifts.
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In 20 trained athletes, the benchmark workout "Fran" was 62% aerobic, 26% from the fast, lactate-producing system and 12% from the quickest stores. A day later their jump height was still down 8% and their plank endurance 46%, and the authors say recovery "can take >24 hours".
In 12 trained adults, five rounds of power cleans, pull-ups, thrusters and burpees done as fast as possible took 12 minutes at an average heart rate of 171 beats a minute, with blood lactate at 11.2 mmol/L. The same work as an EMOM took 20 minutes at 153 beats a minute, with lactate at 6.5, and felt far easier. In 23 experienced athletes, AMRAP and for-time versions of the same work brought similar heart rates and lactate.
The Compendium of Physical Activities rates kettlebell swings at 9.8 METs (multiples of your resting energy use), vigorous circuits that include kettlebells at 7.5, vigorous calisthenics such as push-ups, pull-ups and burpees at 7.5, and burpee-style high-intensity intervals at 11.0. The UK's National Health Service (NHS) counts circuit training and heavy lifting as very vigorous.
Across 21 studies, no single measure predicted performance. Body composition and high-level competitive experience were the most consistent, and in a third of studies total-body and squat strength went with better scores. These are associations.
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The shoulders take overhead lifts, kipping and ring work, and shoulder injuries came most often in gymnastics moves; the lower back takes the heavy lifts, and back injuries came most often in powerlifting moves. The knees, the wrists and hands (front-rack positions, push-ups, handstands and burpees) and, in women, the pelvic floor (jumping and heavy lifting) take the rest.
Studies count injuries differently: any pain that stops training, time off, or a visit to a doctor. Some ask people to remember a year; others follow them week by week, which finds more. Read each line on its own.
The shoulder takes about a quarter of injuries in high-intensity functional training, most often in gymnastics moves. In one survey there were 1.94 shoulder injuries per 1,000 hours, 39% of them flare-ups of older injuries, and people blamed poor form for about a third. Our shoulder pain, shoulder impingement, rotator cuff tear, SLAP tear and shoulder dislocation guides cover them.
The back takes about a quarter of injuries, most often in powerlifting moves such as squats and deadlifts. Our back pain, herniated disc and back spasm guides cover them.
The knee takes 14 to 18% of injuries. In group strength and endurance classes, burpees and squats were the moves most often being done when people got hurt. Our knee pain, runner's knee and jumper's knee guides cover them.
Wrists, hands and fingers take about 12% of injuries. Of 270 athletes, 20% had had a hand or wrist injury, mostly the wrist; 29% hurt the same wrist again, and most went back to full training within a month, often without seeing anyone. Our wrist pain, wrist pain from push-ups and TFCC (triangular fibrocartilage complex) tear guides cover them.
The elbow takes about 10% of injuries in pooled studies, and 12% in the largest survey. Our elbow pain, tennis elbow and golfer's elbow guides cover them.
168 novices in an 8-week start-up programme had 9.5 injuries per 1,000 hours, more than most studies of experienced members report. In a survey of 3,049 people, those in their first year were more often injured, and a short time in the sport was the clearest marker of injury, at 1.8 times the odds. In other studies, experience went with fewer injuries.
The novice study was short, two of its authors worked part-time at the gym, and studies define injuries differently, so the comparison is rough. That's why we grade it emerging.
A previous injury went with 2 to 4 times the risk in three studies that followed people forward. Switching between the prescribed load and a scaled one went with 3.5 times the odds of injury, and each extra hour of training a week with 35% more risk. Men were injured more often in two studies, and trainer involvement went with fewer injuries. Of 837 people treated for CrossFit injuries in one US health system, 11.2% came back with another, more often if they were older. All of these are associations.
One review lists competing among the risk factors reported in CrossFit studies. But the largest study of it, a survey of 3,049 people, found competitors had no higher injury rate: 0.21 to 0.54 injuries per 1,000 training hours, against 0.39 to 1.30 for those who didn't compete.
No study gives injury rates for children doing CrossFit-style training. In one children's hospital sports clinic, CrossFit injuries made up a growing share of visits, and injured athletes aged 19 and under more often had trunk or spine injuries than older ones. These are case series of injured patients. Our exercise for children guide covers supervised strength training.
32 recreational CrossFit athletes in Madrid were randomised to mobility and stability exercises during the warm-up of every session for 10 weeks, or their usual warm-up. Injuries were rare, 0.04 per 1,000 training hours, with no differences between the groups in injuries, their severity, training load, pain or fatigue. The abstract doesn't give the exercises, doses or how many sessions people did.
A trial this small, with so few injuries, can't show a benefit or rule one out. We found no other prevention trial in CrossFit or high-intensity functional training.
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Being new is the most consistent injury marker. Our suggestion: two or three coached classes a week with a day between, loads light enough to learn the lifts, fewer for-time workouts, and sets that stop 2 to 3 reps short of failure (editorial).
Trainer involvement went with fewer injuries, and a review of three cohorts found more injuries without supervision. CrossFit itself says "Every CrossFit class is coached". Learn the Olympic lifts and gymnastics moves in a coached class, and build a strict pull-up before kipping, as our pull-up guide advises.
Switching between the prescribed load and a scaled one went with 3.5 times the odds of injury, one of only two factors with consistent, if limited, evidence across the studies that followed people forward. Our suggestion: choose a scale you can hold for weeks and progress it steadily, rather than jumping to the full weight on good days (editorial).
A previous injury was the most consistent risk marker, 39% of shoulder injuries in one survey were flare-ups of old ones, and many wrist injuries went back to full training within a month. Finish the stages of the matching pain guide, then come back with scaled loads.
In 295 athletes followed for 9 months, each extra hour of training a week went with 35% more risk, and higher self-control scores with 73% less: scaling down when you're tired seems to matter (our reading). Keep at least one full rest day a week, as our rest days guide explains (editorial).
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No study has tested a shoulder programme in CrossFit. Rotator cuff and shoulder-blade work, borrowed from other overhead sports, is our suggestion (editorial). For the back, coaching, steady loads and our squat and deadlift guides are the practical answers. For the wrists, build up handstands, front-rack positions and burpees gradually, and use our wrist and forearm routine.
Across 25 randomised trials in many sports, strength training programmes cut injuries to under a third, while stretching made no difference. This hasn't been tested in CrossFit itself.
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A 2011 consensus on "extreme conditioning programs" in the US military found "an apparent disproportionate musculoskeletal injury risk from these demanding programs, particularly for novice participants". Later reviews found injury rates like those in weightlifting and other recreational sports. Both fit if the risk lies more in how a programme is coached and progressed than in the movements themselves (our reading).
Warm-ups haven't been shown to prevent CrossFit injuries: the pilot trial found no effect, and in 502 Israeli athletes those who warmed up reported more injuries, probably because people with pain warm up more. Warm up for a better session, as our warm-up guide explains. A movement screening test didn't clearly predict who would be injured.
Across 19 studies of people aged 10 to 23, high-intensity functional training improved strength, power, speed, endurance and agility, with large effects, but not flexibility, and the evidence was low certainty. A 2018 review found only 2 CrossFit studies with a high level of evidence and no clear effects in the 4 it could combine, though members reported a strong sense of community, satisfaction and motivation.
Body composition and competitive experience were the most consistent predictors across 21 studies, and strength in a third of them. No single test tells you how you'll do.
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EMOMs build rest into every minute and kept heart rate, lactate and effort well below a for-time version of the same work, so they suit learning technique and easier days. For-time workouts and AMRAPs are the hard days (our reading, as in our EMOM and AMRAP guide).
Across 43 studies, adding aerobic training to strength training didn't reduce gains in maximal strength or muscle size, but it did reduce gains in explosive strength, mainly when both were done in the same session rather than at least 3 hours apart.
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Our suggestion for your first 3 months: two or three classes a week, at least a day between hard ones, one of them focused on strength or skill, and easy aerobic work such as zone 2 cardio on other days. Build to three or four classes a week only if you're recovering well. If you also run or race Hyrox, our running and Hyrox pages cover the order and spacing (editorial).
Rhabdomyolysis is a breakdown of muscle whose contents can harm the kidneys. MedlinePlus lists "Severe exertion, such as marathon running or calisthenics" and severe dehydration among its causes, and dark, red or cola-coloured urine, passing less urine, weakness, and muscle aching or tenderness among its signs.
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At one US academic hospital, 11 of 523 people treated for CrossFit injuries over 6 years (2.1%) had rhabdomyolysis. They averaged 35 years old, more than half were beginners, 91% had dark urine and more than half had pain in their arms; they waited about 3 days before coming in, and stayed in hospital about 3 days.
In two case reports, a 31-year-old woman had arm pain 2 days after a workout and spent 2 days in hospital, and a trained 35-year-old woman developed it after a 2-day competition that included 60 GHD sit-ups (on a glute-ham developer), a move she wasn't used to, with muscle pain for 25 days.
Exertional rhabdomyolysis follows exercise you're not used to, extreme heat, and some drugs and conditions, and happens where "exercise is improperly prescribed or used as punishment"; creatine doesn't seem to trigger it. Statins are among the drugs that can cause it. Across 772 athletes, most cases followed running or weightlifting.
Build volume over weeks, especially for new moves with a lot of lowering: GHD sit-ups, jumping lunges, high-rep pull-ups and push-ups, and box jumps. Start GHD sit-ups at the move guide's dose of 3 sets of 5 partial-range reps, and don't do a new move for time or for very high reps in your first sessions. Drink after hard sessions, and don't train hard while you're ill or in heat you're not used to (our suggestions, built on the reviews).
Across 13 surveys of 4,823 women who do CrossFit, 44.5% reported leaking urine, mostly stress leaking, and more often with age, a higher body mass index and after having children. "Exercises based on jumps were commonly associated with urine leakage". The studies were of poor to fair quality.
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In Norway, 47 women with an average age of 33.5 who did functional fitness such as CrossFit and had stress leaking were randomised to a 16-week home programme of 3 sets of 8 to 12 maximum pelvic floor contractions a day, with a weekly phone reminder, or to a control group. 64% of the training group reported less leaking, against 8% of the others, and their leaking scores improved more, though pelvic floor strength and prolapse symptoms didn't differ. On average the women did 70% of the programme.
Our pelvic floor guide and pelvic floor exercises workout cover how to do them.
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Don't start a new vigorous activity in pregnancy, as our pregnancy guide says. If you already train, one study compared 44 women who kept training CrossFit-style, with changes, into the third trimester with 88 women who didn't, and found no difference in preterm birth, birth weight or complications. It looked back at records, so it's reassuring for people already training, not a reason to start. Talk to your midwife.
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Built on CrossFit's own class structure and the site's warm-up guide (editorial). No study has shown that a CrossFit warm-up prevents injuries: the one trial found no effect, so warm up for a better session.
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The movement on the figure: World's greatest stretch
Each has a 3D demo, and each move guide carries its own cautions. Double-unders, wall balls, rope climbs and kipping aren't on the figure yet, so the workouts use the closest moves.
3D demoKettlebell swingIntermediate · A kettlebell
3D demoDumbbell goblet squatIntermediate · A dumbbell
3D demoBarbell back squatAdvanced · A barbell
3D demoBarbell deadliftAdvanced · A barbell
3D demoPower cleanAdvanced · A barbell
3D demoDouble kettlebell thrusterAdvanced · A kettlebell
3D demoPush-upIntermediate · No equipment
3D demoPull-upAdvanced · Pull-up bar
3D demoInverted rowIntermediate · Pull-up bar
3D demoBurpeeAdvanced · No equipment
3D demoBox jumpIntermediate · A bench or box
3D demoGHD sit-up (glute-ham developer)Expert · An anchor point
3D demoMuscle-upExpert · Pull-up bar
3D demoIndoor rowing (rowing machine)Beginner · Cardio machineThe first two are new: a beginner session in the shape of a class, and a warm-up and mobility routine. The technique workouts teach the lifts, and the progressions build strict pull-ups and handstands before you kip or kick up.
A 45-minute beginner session in the shape of a CrossFit class: a warm-up, goblet squats, deadlifts, push-ups and rows, a 10-minute EMOM, then core work.
45 minBeginner15 movesCardio machine, A wallA 15-minute warm-up and mobility routine for CrossFit-style training: easy rowing, shoulder, wrist, hip and ankle mobility, shoulder-blade work and squats.
15 minBeginner14 movesCardio machine, A wallA 16-minute EMOM: start squats, push-ups, lunges or jumping jacks at the top of each minute and rest for what's left, with easier and harder targets.
22 minBeginner9 movesA wallA full-body circuit of 8 stations: dumbbell squats, push-ups, rows, lunges, deadlifts and cardio moves, 40 seconds each, for 2 or 3 rounds.
35 minBeginner14 movesA dumbbell, A bench or boxA 25-minute practice session for your first kettlebell swings: hip hinge drills, kettlebell deadlifts, then short sets of swings with a park after each.
25 minBeginner8 movesA wall, A kettlebellA 25-minute practice session for the squat: find your depth on a chair, groove the bodyweight squat with pauses, then load it with a slow goblet squat.
25 minBeginner8 movesA wall, A bench or boxA 30-minute session from the hip hinge to your first deadlift: hinge practice, kettlebell deadlifts, slow Romanian deadlifts, a light bar and a carry.
30 minBeginner9 movesA kettlebell, A dumbbellA 30-minute practice session for the overhead press: check your overhead reach, groove it with a band and seated dumbbells, then press the empty bar.
30 minBeginner9 movesA band, A wallTrain for your first pull-up: hangs, shoulder-blade pulls, rows, band- or machine-assisted pull-ups, slow negatives and grip work in one session.
30 minBeginner8 movesPull-up bar, A stepWork up to your first pull-up: dead hangs, scapular pulls, rows, negatives and assisted pull-ups.
25 minBeginner7 movesPull-up bar, A stepBuild toward a handstand: wrist prep, dolphin pose, pike push-ups, crow, the wall handstand and freestanding holds.
25 minAdvanced8 movesA wallA 25-minute band routine for healthy shoulders: move the shoulder and upper back through their range, then strengthen the rotator cuff and shoulder blades.
25 minBeginner12 movesA wall, A bandWrist mobility and forearm strength for desk work, climbing, push-ups and handstands.
10 minBeginner7 movesA wall, A dumbbellA 5-minute daily pelvic floor workout for women and men: slow holds and quick squeezes, three times a day, with how to find the right muscles.
5 minBeginner2 movesNo equipmentOur beginner strength programme teaches the main lifts two or three times a week, a good base before classes.
A 12-week beginner barbell program: squat every session, alternate bench and row with press and deadlift, and add weight each time until it stalls.
3 training days50 minBeginner3 days a weekAn 8-week kettlebell plan for beginners: two strength sessions and a swing-interval day each week, with how to choose a bell and swing safely.
3 training days35 minBeginner3 days a weekA 12-week calisthenics plan for beginners: three bodyweight sessions a week with push-up, pull-up, squat and dip ladders, and a bar if you have one.
3 training days40 minBeginner3 days a weekFor after about 8 weeks of a beginner plan: three full-body sessions a week, one heavy, one moderate and one light, in a gym or at home, for 12 weeks.
3 training days50 minIntermediate3 days a weekA beginner gym plan: three full-body sessions a week, alternating workouts A and B, with sets, reps, rest and an 8-week progression.
3 training days45 minBeginner5 days a weekA 12-week first Hyrox plan: three runs, two strength sessions and one stations-and-runs session a week, built up to race weights, with a taper and race tips.
5 training days50 minIntermediateThe NHS advises speaking to your GP first if you haven't exercised for some time, or if you have medical conditions or concerns. The Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) asks about a heart condition or high blood pressure, chest pain, dizziness or fainting, other long-term conditions and their medicines, and bone or joint problems. A yes to any of them means checking first.
The PAR-Q+ asks you to see a qualified exercise professional before vigorous to maximal exercise if you're over 45 and not used to it. Workouts done for time took trained adults to an average heart rate of about 171 beats a minute.
See your GP before high-intensity sessions.
A previous injury was the most consistent injury marker, and many people go back too soon. Finish the matching pain guide's stages first, then return with scaled loads.
Don't start CrossFit new in pregnancy; if you already train, talk to your midwife, and see our pregnancy guide. After having a baby, or with leaking or a feeling of heaviness, our postpartum and pelvic floor guides help, and a pelvic health physiotherapist can assess you.
Avoid deep, repeated rounding of the back with weight, as our osteoporosis guide explains. Hinge from the hips, and ask a physiotherapist which lifts suit you.
Build strength and control before high-impact and gymnastics work, as our hypermobility guide explains.
Statins are among the drugs that can cause rhabdomyolysis, and our hypothyroidism guide explains how an untreated underactive thyroid can cause it too. Build up gradually, and see your GP if your muscles ache badly.
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Supervised strength training is safe for children, as our exercise for children guide explains, but no study gives injury rates for children doing CrossFit-style training. Look for a qualified coach who scales the workouts for age.
Dark, red or cola-coloured urine, much less urine than usual, or very painful, weak or swollen muscles in the days after a session: get medical help the same day.
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Call 999 for sudden chest pain that doesn't go away, pain that spreads to your arms, neck, jaw, stomach or back, or chest pain with sweating, feeling sick, light-headedness or breathlessness. If someone faints or collapses while exercising, call 999.
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Loss of feeling around your genitals or bottom, new trouble controlling your bladder or bowels, or numbness or weakness in both legs needs 999 or A&E (accident and emergency). Our back pain guide explains why.
A shoulder that slips out or looks out of place, a knee that gives way, locks or swells within hours, or a wrist that's swollen and can't take weight needs checking before you train it again. Our pain guides say what to do.
Injury rates are comparable with Olympic weightlifting, powerlifting and other recreational sports. The risk is higher in beginners, people training without a coach and people with old injuries, which are associations.
It's muscle breakdown that can damage the kidneys and needs treatment. In one hospital's CrossFit cases, more than half the patients were beginners, and they stayed in hospital for about 3 days.
The one trial found no effect, and in a survey people who warmed up reported more injuries. Warm up for a better session.
No study has singled kipping out, though shoulder injuries cluster in gymnastics moves overall. CrossFit advises building a strict pull-up first, and so does our pull-up guide.
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It's common, but daily pelvic floor training improved it for 64% of women in a trial, against 8% without.
One review lists competing as a risk factor, but the largest study found competitors had no higher injury rate.
Every workout can be scaled, but beginners do get hurt more often, so start with fewer, lighter, coached sessions.
For most people it's about as safe as other gym training: studies find injury rates similar to weightlifting, mostly to shoulders, backs and knees. The risk is higher when you're new, train without a coach or come back from an injury too soon, so start with scaled, coached sessions.
Across 28 studies, there were about 4 injuries per 1,000 hours of training, and over a third of people had been injured at some point. Rates range widely because studies define injuries differently, and studies that follow people week by week find more. Beginners get hurt more often than experienced members.
Rhabdomyolysis is a breakdown of muscle that can harm the kidneys, usually after a big, unfamiliar session, such as many sit-ups or pull-ups at once. It's rare, but dark, red or cola-coloured urine, much less urine than usual, or very painful, weak muscles after a session need medical help the same day.
Two or three coached sessions a week, with scaled loads you can keep for weeks and nothing done to failure, while you learn the lifts light. Our beginner workout follows the shape of a class with that in mind.
Yes, with bodyweight, a kettlebell or dumbbells, but keep the volume of new moves low at first: a home workout of hundreds of squats and jumping lunges is a big jump for a beginner. Learn the barbell lifts with a coach.
HIIT repeats short, hard bursts with set rests. CrossFit-style training varies the moves and durations, with or without rest, and mixes in lifting and gymnastics. Both are hard, and our HIIT and EMOM guides cover the formats.
They suit different goals: Hyrox is a fixed race that's mostly running, while CrossFit varies every day and includes more lifting and gymnastics. Their injuries differ too, with knees and lower legs in Hyrox's one study, and shoulders, backs and knees in CrossFit.
In 19 studies, functional training improved strength, power, speed and endurance in young people, but the evidence is low certainty, and few CrossFit studies are high quality. People who do it report a strong sense of community and motivation.
Don't start it new in pregnancy. If you already train, one study of women who kept training, with changes, into the third trimester found no difference in birth outcomes. Talk to your midwife, and see our pregnancy guide.
Stress leaking is common in women who do CrossFit, especially with jumping. Sixteen weeks of daily pelvic floor training improved it for most women in a trial, and our pelvic floor guide explains how to do it.
Exercise education for people who play sport, not a personal prescription or a diagnosis, and clinical review of these pages is pending. Check with a GP or physiotherapist before hard training if you have a heart condition, chest pain, dizziness or an injury that isn't settling, and stop for sharp or increasing pain. Health disclaimer.
