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Indoor Training

This is Why Your Butt Hurts on the Bike Trainer

For many, riding the bike trainer can be a royal pain in the butt. One physical therapist breaks down what’s going on down below when things go south.

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Riding indoors on the trainer can be all sorts of painful. Not only is it tough mentally, but physically you feel it in your heart, lungs, legs…and especially in the netherlands/downtown/unmentionables area. It is only natural that when your butt hurts on the bike trainer, you’ll assume it’s just how it’s supposed to be. But if you can pinpoint the cause of your undercarriage trouble, you can find solutions. When self-diagnosing this problem, you will find plenty of information on saddle choices, gear (such as trainer platforms), and a lot of opinions on what constitutes a proper bike fit. We could chase the symptoms and address all this and more, but that would be a real pain in the…well, you get it.

The crux of the problem with riding the trainer opposed to out in the great outdoors is pressure. Riding indoors results in a static position that causes very specific, sustained pressure on very specific tissues. Riding outdoors is dynamic, allowing you to weight transfer and have complete pressure relief during periods of cornering and standing while climbing and sprinting. It is this prolonged pressure that is the source of your butt pain on the bike. Your issues could be a result of any variety of the following complications associated with prolonged pressure while riding the trainer.

RELATED: Indoor Training for Triathletes

Why does my butt hurt on the bike trainer?

Ischial Bursitis

Throughout your body, you have bursae, or cushions placed in the space between a bony prominence and tendons. Your ischial tuberosities, better known as “sit bones,” have bursae that reside on top of them as well. Prolonged sitting on a firm surface, without pressure relief, can lead to this painful inflammatory condition. Ischial bursitis is also known as weaver’s or tailor’s bottom, because it refers to professions that historically worked long days on hard seats. Advanced bursitis will require rest, anti-inflammatory medication, or possibly cortisone injections.

Ischemic Pain

Ischemic pain is a result of hypoxia, or lack of oxygen to tissue due to restricted blood flow. Pressure will occlude—or block—the blood vessels, restricting blood flow to the working muscles resulting in pain as the muscle tries to work in an environment void of necessary oxygen.

Nerve Pain

Typical nerve pain is due to neuropraxia (temporary blockage of nerve conduction) of the sciatic nerve. Think of stepping on a hose and noticing the flow of water diminish. This blockage can lead to pain, sense of numbness/tingling, and loss of strength.

Pudendal Neuralgia

Your body weight is supported on your ischial tuberosities, and to an extent the soft tissues of your perineal area where the pudendal nerve resides. The pudendal nerve is a main nerve in your pelvic region and prolonged or excessive pressure on the pudendal nerve will result in numbness and pain. Your soft tissues can sustain some pressure for brief amounts of time, but to avoid numbness and pain caused by occlusion of nerves and blood vessels, frequent pressure reduction is essential. This is where saddle choice and bike fit are important.

Bacterial Skin Infection (Cellulitis)

No need to sugar coat it: You get next-level sweaty during trainer sessions. Though this affliction less about pressure, it’s still a potential source of pain in your butt on the bike. Wash up right after workouts, and keep chafing at bay with appropriate bibs and chamois cream.

My butt hurts on the bike trainer. What do I do?

Get off your A$#!!! Really. Frequent pressure relief through standing, shifting around on your saddle, and cross-training (i.e., taking a rest from the trainer) helps reduce the potential for injury. Additionally, do not cheap out on the chamois in your bike shorts for the indoor sessions. We all have the tendency to want to wear our old bib shorts for trainer sessions and save our fancy ones to show off on the group rides. However, the chamois in your old, transparent bibs will not be as good as the one in your new shorts and that lack of support leads to…you guessed it, increased pressure.

A proper bike fit that takes gender-specific and person-specific saddle choice into account is important for providing the proper position for comfort and efficiency. Finally – and I cannot emphasize this enough – load up on the chamois cream (our picks below). This will reduce unnecessary friction and provide a protective barrier for your skin for that sweaty environment. A little extra attention on the front (or rather back) end will help ensure more comfort during your trainer sessions, so you can suffer where intended!

RELATED: The Best Triathlon Saddles

Products that can help (aside from the right saddle, of course)

Saris MP1 Nfinity Motion Platform

$950, saris.com

If your butt hurts on the bike, PTs recommend this platform

It’s not cheap, but this novel, wood-constructed trainer platform fits nearly all trainers and provides controlled motion in the side-to-side and front-to-back planes. Though it’s stiff enough not to feel wobbly and take away your attention from the workout, it still provides a staggering amount of pain relief for rides of any length. Though Saris touts the platform’s ability to provide an extra core stability workout (which it does), in terms of pain relief, there’s not much else available that works as well. The only downside (aside from the price tag) is the very heavy, very tough-to-move piece of equipment is not conducive to temporary trainer locations. You’ll only want this if you have a dedicated pain cave.

Castelli Insider 2 Bibshort

$150, castelli.com

If your butt hurts on the bike, pts recommend these shorts

Leave it to premium cycling clothing brand Castelli to create a trainer-specific clothing line. While their Insider jersey is nice for completists, if you’re going to spend on just one piece of indoor-specific clothing, pick up the Insider 2 bibshort. In Castelli’s own words, this piece uses fabric that is “just enough to hold everything secure without being transparent,” so expect tons of cooling air flow, wicking, and evaporation. Even the bib straps are super minimal to just barely keep the shorts up, without creating additional, unnecessary coverage and heat. As such, this pair of bib shorts is the exception to the rule of wearing strapless shorts while riding inside.

RELATED: How to Find the Right Bike Shorts for You

Muc-Off Luxury CC Chamois Cream

$15 for 100ml, us.muc-off.com

If your butt hurts on the bike, PTs, recommend this chamois cream

Part of its athlete performance line, Muc-Off has created a chamois cream with an exceptional viscosity. This is a well-balanced and durable cream that provides comfort and eliminates chafing even during long rides. There is a noticeable cooling effect with this product, so be prepared.

RELATED: Chamois Cream: 5 of Our Favorite Options

Casey Maguire is a Los Angeles-based orthopedic physical therapist who has treated professional triathletes, cyclists, and multiple athletes in the NBA, NHL, NFL, and USTA. His focus is on functional biomechanics.