Written by Fairuuz Saleh, Principal Physiotherapist, and Yuna Zhuang, Principal Hand Occupational Therapist, at Phoenix Rehab. Clinically reviewed by Louise Yow, Principal Physiotherapist & Director, AHPC A1300363H; hand, wrist and elbow sections by Nigel Chua, Principal Hand Occupational Therapist & Director, AHPC A1300362Z. Last reviewed 12 October 2026.
Most spin class injuries are overuse problems at the knee, the lower back and neck, the hands and the feet, and many trace back to saddle height, handlebar reach and how quickly classes were added. A saddle set too low raises the load behind the kneecap.1 Rarely, a first hard class causes rhabdomyolysis, which needs the emergency department.2
Spin in Singapore is a dark room, loud music and 45 minutes on a bike with a heavy flywheel. A studio in the CBD before work, a condo gym at lunch, a class at the community club on Saturday morning. The riders we see are mostly in their twenties to forties, riding three to five classes a week, often on a class package bought with a fitness goal in mind.
The bike does not let you coast. The flywheel keeps the pedals turning, the resistance knob goes up on every climb, and the room rides together to the beat. Rhythm classes add choreography on top: push-ups on the handlebars, tap-backs, hovers out of the saddle. A first-timer sets the bike once, quickly, in the dark, and rides that setup for months.
So the injuries split two ways. Most build over weeks: the knee that aches on the MRT station stairs the morning after, the lower back that stiffens by the third climb, the ring and little fingers that tingle on the laptop mouse that afternoon, the shoe strap loosened halfway through because the ball of the foot is burning. A few arrive after one class, and the one to know is rhabdomyolysis, covered under the doctor-first signs below.
Wrist, hand and elbow problems on this page, including numb fingers, are seen by our hand therapy team. Everything else is seen by our physiotherapy team. Riding outdoors brings its own set, covered in cycling injuries.
The movements, and what they load
| Movement | What it loads | What it most often irritates |
|---|---|---|
| Seated climb at heavy resistance | The front of the thigh, the kneecap and the tendon below it | Kneecap pain, pain below the kneecap |
| Standing climb and sprint, out of the saddle | Knees, calves and Achilles tendon, with more body weight through the hands | Pain below the kneecap, Achilles tendon pain, wrist pain |
| Fast pedaling at high cadence, light resistance | The hip flexors and the outer knee, thousands of times a class | Hip flexor strain, outer knee pain (IT band) |
| Riding low and forward for the whole class | Lower back, neck, shoulders, and the nerves at the wrist and elbow | Low back strain, neck pain, numb fingers |
| Choreography: push-ups on the handlebars, tap-backs, hovers | Wrists bent back under load, shoulders, lower back | Pain at the back or the little-finger side of the wrist, low back strain |
| Feet clipped in or strapped for 45 minutes | The ball of the foot and the top of the foot | Hot foot (burning or numb toes), pain on the top of the foot |
| A first class, or the hardest class in months | The thigh muscles | Delayed muscle soreness, and rarely, rhabdomyolysis |
Every spin class injury, by body part
Start from where it hurts. Rows with a link go to the page that covers that injury in full.
| Where | Injury | How spin class usually causes it |
|---|---|---|
| Knee | Pain around or behind the kneecap (patellofemoral pain) | A saddle set too low, so the knee stays deeply bent under heavy resistance |
| Knee | Pain below the kneecap (patellar tendinopathy) | Heavy climbs and standing sprints added faster than the tendon adapts |
| Knee | Pain at the back of the knee (hamstring tendons) | A saddle set too high, so the leg overreaches at the bottom of each stroke |
| Knee | Outer knee pain (iliotibial band, IT band) | A saddle set too high, or a foot turned in or out on the pedal, repeated through a fast class |
| Hip | Hip flexor strain, or an ache at the front of the hip | High cadence with the hip closed up under low, far handlebars |
| Tailbone | Tailbone pain (coccydynia) | Sitting upright and far back on a firm saddle |
| Lower back | Low back strain | A whole class rounded forward, with the handlebars too low or too far away |
| Lower back and leg | Sciatica (back pain with pain down the leg) | Long stretches bent forward on a back that was already irritable |
| Neck | Neck pain | Head tipped back to watch the instructor or the screen from a low position |
| Neck and shoulder | Ache at the side of the neck and top of the shoulder blade (levator scapulae) | Shoulders shrugged and elbows locked, leaning weight onto the bars |
| Elbow | Ulnar nerve at the elbow (cubital tunnel): tingling in the ring and little fingers | Elbows held bent for the whole class, or leaning on the forearms |
| Wrist and hand | Handlebar palsy (ulnar nerve at the wrist, Guyon’s canal): numb ring and little fingers | Body weight on the heel of the hand, little-finger side, for 45 minutes |
| Wrist and hand | Median nerve at the wrist (carpal tunnel): numb thumb, index and middle fingers | Wrists bent back with weight through the palm |
| Wrist | TFCC injury (the cartilage on the little-finger side of the wrist) | Weight on the bars with the wrist bent toward the little finger, and handlebar push-ups |
| Wrist | Ache on the back of the wrist (dorsal wrist pain, sometimes a ganglion) | Leaning on bent-back wrists through choreography |
| Thigh | Exertional rhabdomyolysis (severe muscle breakdown). Doctor first: see below | A first class, or a much harder class than usual, at heavy resistance |
| Lower leg | Achilles tendon pain | The heel dropping and lifting through every stroke under heavy resistance |
| Foot | Hot foot: burning or numb ball of the foot (metatarsalgia, sometimes Morton’s neuroma) | Pressure through the ball of the foot on a small pedal or cleat, in a tight shoe |
| Foot | Pain on the top of the foot (extensor tendon irritation) | Pedal straps or shoe straps pulled tight over the top of the foot |
Not on the list, or not sure which row is yours? That is what the first visit is for.
The common ones, in more depth
Front-of-knee pain, and the saddle that is too low
This is the knee pain people search for after spin. An ache around or behind the kneecap, worse on stairs, worse standing up after sitting through a meeting. A low saddle keeps the knee deeply bent at the top of every stroke, and a review of the saddle height research found the compressive load behind the kneecap goes up as the saddle goes down.1 Heavy resistance multiplies it. Pain just below the kneecap is usually the patellar tendon instead, from climbs and standing sprints added faster than the tendon adapts. We test a single-leg squat and step-down on each side, and compare thigh strength between the legs.
Back-of-knee and outer knee pain, and the saddle that is too high
Set the saddle too high and the leg overreaches at the bottom of the stroke. The hips rock side to side to find the pedal, and the hamstring tendons behind the knee take a stretch on every turn. The outer knee is the other one: pain at the same point in each class, on the outside of the knee, often with a foot turned in or out on the pedal. That is usually the iliotibial band. In our experience it settles with a change in setup and load more than with stretching alone.
The lower back and neck in the forward position
A spin bike puts you low and forward for 45 minutes, and the room rarely sits up. The lower back holds that curve under every climb. The neck tips back to watch the instructor or the screen. When the handlebars are low and far away, both work harder. We watch how far the hips hinge before the back starts to round, and time how long you hold the riding position before it hurts. Back pain that comes with pain, numbness or weakness down the leg is a different thing, and is listed in the doctor-first signs.
Numb fingers, handlebar palsy and the wrist
Numbness in the ring and little fingers after class is usually the ulnar nerve, pressed where it runs through the heel of the hand on the little-finger side. In cyclists this is called handlebar palsy, the cycling form of Guyon’s canal syndrome.3 Numbness in the thumb, index and middle fingers is usually the median nerve, at the carpal tunnel, from wrists bent back with weight through the palm. Numbness that goes within minutes of getting off the bike is pressure. Numbness that lasts for days, or a hand that turns clumsy, is the nerve itself and needs a doctor soon. We test sensation in each finger, grip and pinch strength, and the strength of the small muscles that spread the fingers, against the other hand. Push-ups on the handlebars add a second load: an ache on the back of the wrist, or on the little-finger side, from leaning on wrists bent back.
Hot foot and the Achilles
A burning or numb ball of the foot by the third song is called hot foot. It is pressure on the nerves between the long bones of the foot, from a small pedal or cleat and a shoe done up tight in a warm room. Loosening the strap mid-class helps for a few minutes. The cleat or pedal position, the shoe and the foot are what we look at. Achilles tendon pain comes from the heel dropping and lifting on every stroke under heavy resistance, and from climbs out of the saddle. Single-leg heel raises, counted on both sides, tell us how much load the tendon is ready for.
The bike setup we check
Setup is part of the assessment, because it is part of the load. These are the things we check on a bike with you, and none of them is one number for everyone:
- Saddle height: the bend left in the knee with the pedal at the bottom of the stroke. Research on cyclists puts it at about 25 to 30 degrees.1
- Saddle fore and aft: where the knee sits over the pedal with the cranks level.
- Handlebar height and reach: how far you fold forward, how much weight goes through the hands, and how far the neck tips back.
- The foot: the ball of the foot over the pedal axle, the cleat angle matching how your feet sit, and straps snug rather than tight.
Most studio bikes have numbered settings. Once the setup suits you, write the numbers down, so the next bike in the next class is set the same way.
Return on tests, not dates
Pain going away is the first sign, not the last. These are the checks we use before a full class at full resistance:
- Knee: single-leg squat and step-down on each side without pain, and thigh strength close to the other leg.
- Back and neck: holding the riding position for the length of a class without pain building, and no flare the next morning.
- Hand and wrist: no numbness or tingling after a ride, grip and pinch strength close to the other hand, and the small hand muscles equally strong on both sides.
- Achilles and foot: single-leg heel raises counted on both sides and close to each other.
- After rhabdomyolysis: your doctor clears you first, then classes start short and light, and build from there.
Then volume comes back in steps: a shorter class at lighter resistance, then a full one, then classes on back-to-back days.
Is this normal?
Sore thighs for one to three days after a first class, easing each day, is usual. Sore sit bones for the first few classes are common and ease as you ride more. Numb fingers, toes or groin that come back within minutes of getting off the bike are pressure, and worth a setup change. Muscle pain that is getting worse two or three days later instead of easing, with swelling or dark urine, is not normal, and is in the next section.
When to see a doctor first
- Call 995 for chest pain, collapse, fainting or severe breathlessness during class.
- Emergency department now for severe muscle pain and swelling, usually in the thighs, a day or more after a first or very hard class, with dark, cola-colored urine; or numbness around the groin or saddle area that stays after you get off the bike, with back pain or a change in bladder or bowel control.
- Doctor the same day for muscle pain far beyond normal soreness that is getting worse rather than easing, even if your urine looks normal; or a calf that is swollen, hot and painful.
- Doctor soon for finger numbness that lasts for days after class, or a hand that has turned weak or clumsy; or back pain with pain, numbness or weakness down the leg.
Rhabdomyolysis is muscle breaking down faster than the body can clear it, and the contents can harm the kidneys. One hospital in Korea reported 11 cases, every one after a first spin class.2 Dark urine is the sign not to wait on. Drinking water at home is not the treatment for it.
Questions people ask
What is the most common spin class injury?
Knee pain is one of the most common spin class injuries, around or behind the kneecap or just below it, often linked to saddle height and heavy resistance. Lower back and neck ache, numb fingers and a burning ball of the foot are also common. Most are overuse injuries that build up over several classes.
Why does my knee hurt after spin class?
Where it hurts gives the clue. Pain at the front of the knee often goes with a saddle set too low and heavy climbs. Pain at the back of the knee often goes with a saddle set too high. Pain on the outside of the knee is often the iliotibial band, linked to foot position and saddle height.
Why does my lower back hurt after spin class?
Spin holds you low and forward for the whole class, and the lower back holds that position under every climb. Handlebars set low or far away increase the load. Back pain that comes with pain, numbness or weakness down the leg should be checked by a doctor before you ride again.
Is dark urine after a spin class serious?
Yes. Dark, cola-colored urine with severe muscle pain and swelling after a first or very hard spin class can be exertional rhabdomyolysis, a breakdown of muscle that can affect the kidneys. It needs assessment at an emergency department straight away, not rest at home or extra water.
Where are you with this right now?
1. It is settling on its own
If the knee is easier each week since the saddle went up, or the fingers no longer tingle since you took weight off the bars, you are on the right road. Add classes back in steps, one more a week at a time. You do not need us for this, and we would rather say so.
2. It has stopped improving
The knee still aches on the MRT stairs the morning after every class, two months on. You have raised the saddle, written the numbers down, iced it after every ride. You keep the resistance lower than the rest of the room and sit out the standing climbs. The ring and little fingers still tingle on the laptop mouse that afternoon. That pattern is usually a strength and load problem, and rest alone rarely changes it. It is worth measuring. If it has been months, the Stalled Recovery Review is three visits over three weeks with the same therapist.
3. You have had surgery, or you have a date
A knee arthroscopy, an ACL reconstruction, a hip arthroscopy, a lumbar microdiscectomy or a cubital tunnel release each has a shape, with protected weeks first. A stationary bike often comes early in the plan. A full class with standing climbs and choreography comes later, once the criteria for that stage are met. See the Hip Arthroscopy Recovery Program, the Lumbar Microdiscectomy Recovery Program, the Cubital Tunnel Recovery Program, physiotherapy after surgery, hand therapy after surgery and the recovery programs. All of it runs on the four stages of The Phoenix Recovery Protocol.
What our patients say
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Next step
Find out which stage you are in
Pain is the first thing to leave. Strength is the last thing trained back, and most people go back to class before that part is done. One Assessment and Treatment is a single 45-minute appointment at $230, nett, no GST. Your therapist finds what is limiting your knee, your back or your hands, treats it in the same appointment, and you leave with your current stage and a written plan.
Prefer to phone? Each of our five clinics has its own number on the clinics page. No referral needed to book.
Related reading
Sources
- Bini R, Hume PA, Croft JL. Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Med. 2011;41(6):463-476.
- Kim D, Ko EJ, Cho H, Park SH, Lee SH, Cho NG, Lee SY, Jeong HY, Yang DH. Spinning-induced rhabdomyolysis: eleven case reports and review of the literature. Electrolyte Blood Press. 2015;13(2):58-61. doi:10.5049/EBP.2015.13.2.58.
- Kopcik K. Guyon canal syndrome and handlebar palsy: summary of available knowledge. J Pre-Clin Clin Res. 2023;17(1):23-26. doi:10.26444/jpccr/159709.
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