I started noticing a deep, pinching ache in the front of my right hip about three weeks into a heavier ultra block last autumn. Same story I hear from the runners I coach: it felt fine warming up, sharp on the first kilometre, dull for the rest of the run, then nasty going up stairs that evening. Most people, when this hits, do exactly the wrong thing. They stretch it. They roll it. They book a massage. They tell themselves the hip flexor is "tight" and try to lengthen it harder.
A cranky iliopsoas is almost never a flexibility problem. It is a load-management problem. The tendon has been asked to do more than it can currently handle, and the only thing that genuinely changes a tendon's capacity is progressive, well-dosed loading. Stretch a grumpy tendon and you usually make it grumpier. Load it correctly and it adapts.
This is the plan I use on myself and walk my callanetics students and running friends through when the front of the hip starts barking. Four stages, specific numbers, and clear rules for when to push, when to hold, and when to stop and see someone in person.
Why "tight hip flexors" is the wrong diagnosis
The iliopsoas (psoas major plus iliacus) is one of the strongest hip flexors in the body. Its tendon passes over the front of the pelvis and inserts on the lesser trochanter of the femur. Every running stride asks it to absorb force as the leg extends behind you and then concentrically pull the leg through. In hill running, sprinting and tempo work, the demand jumps sharply.
Tendinopathy happens when cumulative load outpaces the tendon's recovery and remodelling capacity. The collagen matrix becomes disorganised, the tendon may thicken, and pain settles in. Classic signs:
- Deep pain in the front of the hip or groin, sometimes referring into the upper thigh
- Worse with the first few steps of running, sit-to-stand, getting out of a car
- Pain stepping up stairs or lifting the knee against resistance
- Often a feeling of "weakness" rather than just stiffness
- Better with gentle warm-up, worse the morning after hard sessions
If you stretch a tendinopathic tendon aggressively, you are compressing it against the pelvic bone and adding tensile load when it cannot tolerate either. That is why so many people feel briefly better after stretching and significantly worse the next day. Stretching is not the enemy forever — it just is not the tool for the first weeks.
The tool is load. Specifically, load that goes up slowly, with feedback rules so you do not blow past your tendon's current ceiling.
The pain rules every stage runs on
Before any exercise, you need two rules in your head. Without them, the plan does not work.
Rule 1: The 24-hour rule. Pain during an exercise is acceptable up to 3 out of 10 (where 10 is the worst pain you can imagine). Pain that lingers more than 24 hours after the session, or that is worse the next morning than it was before you started, means the dose was too high. Back off the load, the volume, or both at the next session.
Rule 2: The trend matters more than the day. Tendons are slow tissue. You will have flare-up days that mean nothing if the seven-day and fourteen-day trend is improving. Track morning stiffness on a 0-10 scale and pain with one provocative test (for hip flexor, usually a single-leg sit-to-stand or stepping up onto a knee-height box). Watch the weekly average, not the daily noise.
With those two rules in place, here is the four-stage progression.
Stage 1: Isometrics (week 1-2, sometimes longer)
Isometric contractions — holding a muscle at a fixed length under load — are the entry point for irritable tendons. They reduce pain, start to load the tendon without the swings of dynamic movement, and let you train the neural side of strength while the tissue calms down.
Three exercises, daily if needed, 5-7 days a week.
Supine hip flexor isometric hold. Lie on your back, knees bent. Lift the painful leg so the hip is at about 70-80 degrees of flexion (knee roughly above hip), knee bent to 90. Press the front of your thigh gently into your own hand or into a band looped over the thigh. Hold a moderate effort — perhaps 50-70% of maximum — for 30-45 seconds. Five repetitions, two minutes rest between holds.
Seated hip flexor isometric. Sit tall on a chair, foot flat. Lift the knee just a few centimetres off the seat and hold against your hand pressing down on the thigh. 30 seconds, 5 reps.
Standing wall march hold. Stand facing a wall, hands on it. Lift one knee to hip height and hold it there for 20-30 seconds, fully relaxed everywhere except the working hip. 4-5 reps each side.
Aim for pain that does not exceed 3/10 during the hold and is no worse than baseline 24 hours later. If you can clear that bar comfortably for 5-7 days, you move on.
Stage 2: Heavy slow resistance (week 2-6)
This is the meat of tendon rehab. Heavy slow resistance training — moving heavy loads through full range at a deliberate tempo — is the most reliable way to drive structural change in a tendinopathic tendon. The research on patellar and Achilles tendinopathy is strongest here, but the same principles apply at the hip.
Two or three sessions per week, with at least 48 hours between them. Three exercises, 3-4 sets each, 6-8 repetitions per set. Tempo is critical: 3 seconds lowering, 3 seconds lifting, no bouncing. The whole rep takes 6 seconds, the whole set takes 36-48 seconds. The weight should be heavy enough that the last two reps are genuinely hard.
Bulgarian split squat. Rear foot elevated on a bench, front foot well forward. Lower under control until the back knee taps near the floor. Drive up slowly. Hold dumbbells at your sides or a single goblet weight at chest. This loads the hip flexor of the rear leg eccentrically as the hip extends — exactly what your tendon needs to learn to tolerate.
Standing cable or band hip flexion. Attach a band or cable to the ankle, facing away from the anchor. Drive the knee up to about 90 degrees of hip flexion against resistance, 3 seconds up, pause at the top, 3 seconds down. This is the most direct iliopsoas loading exercise you can do.
Step-up with control. Step up onto a box at knee height, drive through the front leg, slowly lower back. Add dumbbells once bodyweight is easy. The lowering phase is where most of the tendon adaptation happens, so do not rush it.
Same pain rules apply. The morning after a session you may feel some soreness; if it exceeds your baseline by more than a point or two, the load was too high.
This stage is where most people get impatient. Six weeks feels long when you want to run. But this is the phase that actually changes the tendon. If you skip it or rush it, you spend the next year cycling in and out of the same problem. I have seen this in my own training and in friends I run with — the ones who put in the boring weeks come back fully, the ones who skip ahead keep flaring.
Stage 3: Energy storage and release (week 6-10)
Once heavy slow resistance feels strong and pain has settled to a 0-1/10 baseline, the tendon is ready for spring-like loading. Running is essentially a series of rapid stretch-shorten cycles in the hip flexor and other tissues. Before you go back to running, you need to rehearse that pattern in controlled conditions.
Two sessions per week, separated by 72 hours, while still doing one heavy slow resistance session.
A-skips and high-knee marches. Start with marches, then progress to skips. Focus on driving the knee up sharply, then a relaxed return. Three sets of 20 metres, building over weeks.
Pogo hops in place. Small, bouncy hops with stiff ankles, focusing on quick ground contact. 3 sets of 20 reps.
Single-leg hops, controlled. Hop in place on the affected side for 20 reps, three sets. Then progress to forward, backward, and lateral hops.
Loaded hip flexion at speed. Same band-resisted hip flexion as Stage 2, but now done at a faster tempo: 1 second up, 1 second down, 2-3 sets of 12-15 reps with lighter load.
Pain monitoring stays the same. The morning-after check matters most here, because plyometric load has a delayed cost on tendons.
Stage 4: Return to running
Do not start running until you can complete a full Stage 3 session with no more than 1-2/10 pain and no next-day flare for two consecutive weeks. When you start, start absurdly small.
Week 1 back: Walk-run intervals, 1 minute easy jog and 2 minutes walking, repeated 8-10 times. Twice that week. Yes, that is it.
Week 2: 2 minutes jog, 1 minute walk, 8 rounds. Twice that week.
Week 3: 5 minutes jog, 1 minute walk, building to 25-30 minutes total. Two or three runs.
Week 4 and beyond: Continuous easy running, adding no more than 10% volume per week. No hills, no tempo, no intervals for at least three more weeks after that. Hills and speedwork are the highest-load activities for the hip flexor and they are the last things to add back.
Keep doing one heavy slow resistance session per week throughout this return phase. Forever, ideally. The tendon you rebuilt only stays robust if you keep loading it.
If you are returning from a long lay-off, your foot, ankle and glute strength have also detrained. It is worth pairing this with a foot and ankle routine and gluteus medius work, because a weak glute medius forces the hip flexor to do stabilising work it was never designed for.
Red flags: when to stop and see someone in person
This plan assumes a straightforward overload tendinopathy. Some presentations need an in-person assessment — imaging, sometimes — before you load anything. Stop and see a clinician if you have:
- Sharp groin pain with a clicking, catching or locking sensation in the hip. This can suggest a labral tear or femoroacetabular impingement, which behaves differently and may need different management.
- Pain that wakes you at night, not just discomfort rolling onto the side — true night pain unrelated to position.
- Pain that worsens despite a sensible reduction in load, or no improvement at all after 4-6 weeks of honest rehab.
- A history of long-term corticosteroid use, fluoroquinolone antibiotics, or rheumatologic disease — these raise the risk of partial or full tendon rupture and the plan should be supervised.
- A specific moment of acute injury — a sprint, a fall, a sudden pop — followed by weakness and bruising. That is potentially a tendon avulsion or muscle tear, not tendinopathy.
- Pain referring into the testicles, lower abdomen, or down the leg with numbness or pins and needles. That points to other structures — possibly nerve, hernia, or lumbar referral.
- Fever, unexplained weight loss, or systemic symptoms alongside hip pain. Rare, but worth a same-week appointment.
If anything on that list applies to you, a physiotherapist or sports medicine doctor can rule things in or out with hands-on testing in fifteen minutes. Do not spend three months loading a tendon that turns out to be a labral problem.
What this looks like in real life
The hardest part of this plan is not the exercises. It is the patience. Four stages, often three to four months from start to running properly again, sometimes six months for severe cases. Most people I speak with want a two-week fix. Tendons do not work on two-week timelines. The collagen turnover in tendon tissue is measured in months.
The runners I know who recover fully and stay recovered are the ones who treat the rehab as their training for that block. The session is the workout. The reps are the goal. Running comes back when the tendon is ready, not when the calendar says a race is coming.
A few things that quietly help alongside the loading work: get your sleep in order, eat enough protein (around 1.6-2.0 g per kg of bodyweight if you are training), and look honestly at the training load that caused the problem in the first place. If you went from 40 to 70 km a week, or added two hill sessions, that is the conversation. The tendon told you. It is worth listening before the next block.
The short version
Hip flexor tendinopathy is a capacity problem. The tendon cannot currently handle what you are asking it to do. Stretching does not change capacity. Massage does not change capacity. Only progressive loading does.
Start with isometrics for one to two weeks. Move to heavy slow resistance for four to six weeks, with the lowering phase done slowly and deliberately. Add energy-storage work for three to four weeks. Then return to running with intervals so small they feel embarrassing, building no more than 10% per week.
Pain up to 3/10 during exercise is fine. Pain worse than baseline the morning after is the signal to back off. Watch the weekly trend, not the daily noise. Keep one heavy session in your week forever once you are back.
And if anything on the red flag list applies — sharp catches, night pain, no progress after six honest weeks of work — book the in-person appointment. The plan above is the right starting point for most front-of-hip pain in active people, but no article replaces a hands-on assessment when something is not behaving the way it should.