Tightness — a bit of a stretch?

Nick Ilic Physio Clinician || The Tennis Physio

10 min readJun 24, 2019

March 2022 update: This blogpost is now out of date and I have updated the ideas discussed in a new post. Select here to read it.
I will keep this blogpost here to demonstrate my learning journey and to highlight that good Clinicians are always learning, unlearning and relearning.

Ahhhhh yes… the conundrum of the “tight” hip flexor.

This post was written at a tournament, 2mins after yet another tennis player walked out with hip flexor pain.

He had a “tight” and painful hip flexor. He was getting pain when sliding and reaching to the right on clay court.

Simona Halep on a wide forehand. Her back leg passively going into hip extension with isometric hip flexion to prevent further extension.

His left hip was going into extension whilst stretching for the wide forehands, with the hip flexor actively and passively resisting further extension.

Of course, being a semi-pro/future pro player, overnight he diligently did his hip flexor “stretches” and “trigger pointing” on the hip flexor tendon and came into the treatment room quite sore the next morning.

It’s a misconception that “tightness” is related to a shortening of a muscle/tendon, when in many cases it’s an imbuing/infusing of fluid into the tendon, causing it to swell (aka, ‘swollen tendon’), or it’s “tight” because it’s simply a ‘big thing in a small space’. The tendon will swell in response to load placed on it that exceeds its tolerance/capacity. Whether it is from a high internal load or a high external/compressive load, and sometimes… both.

A high internal load is a fast/powerful change of directions in tendons (‘the spring effect’), which is one of the most challenging loads for a tendon, but it is its primary role.

A high external/compressive load is when the tendon rubs/compresses against something (against bone) or something is compressing it (eg: trigger pointing a tendon, lying on a swollen gluteal (hip) tendon, sitting on a swollen proximal hamstring (butt) tendon).

The attachment of the Achilles Tendon wraps around the bone. Repetitive loaded dorsiflexion (eg: landing from a jump, hill running) can compress the tendon into the bone. See the below picture for a diagram.

You can watch a fantastic video on compressive tendon loads by Running Reform here:

It is these external/compressive loads that are the hardest to manage. They are common at the achilles tendon in the heel, the hip flexor tendon at the front of the hip, the glute tendon on the side and back of the hip and sometimes the high hamstring tendon the buttock where it inserts.

Iliopsoas tendons are known to bigger on the dominant side in tennis players which could also contribute to a feeling of “tightness”.

A bit of a stretch can’t hurt, right?

The number one exercise everyone will choose when they Dr Google their ‘tightness’ is stretches, where you position yourself in a way that puts the target muscle/tendon/soft-tissue on stretch and hold it there.

There’s a time and a place for stretches.

In kids, this has the best effect in terms of increase muscle (sarcomere) length in order to gain “flexibility”. In adults, this does not have a mechanical effect (lengthening), it has more of a neurological effect where the ‘stretcher’ “feels” less tight, for a short-amount of time. In other words, and in research terms, stretching in Adults does not make them more flexible, it increases their tolerance level to stretching, so they feel it less the next time they do it, however there is no change in muscle length. There is an ideal length (or Goldilocks Length) required in tissues, not too tight, not too long, called the length-tension relationship. This Goldilocks length is required as it is the best zone for strength and stability. It a muscle becomes too long, it will be weak, and the joints that it supports and add stability to will have reduced stability.

Being “flexible” later in life (past mid 20s) can cause a myriad of issues, we see more long-term/chronic issues from being “flexible” than from being “tight”, including instabilities around all joints and nerve pain. It’s a misconception that “tightness” results in more injuries that being “flexible”.

If you want to rule out a “shortening” of the hip flexor muscle/tendon or ‘poor flexibility’ you can use the ‘Thomas Test’ (shown below) the differentiate. With the patient/player sitting right on the edge of the bed, get them to grab a knee and lie back and let their other leg dangle off the end of the bed/table. You’re looking for a difference in the angle of the thigh (as shown in Picture 2). However, you then need to differentiate between the iliopsoas hip flexors and the rectus femoris muscle which also crosses the hip joint, you can do this by looking at the difference of passive knee flexion or quads tightness difference.

Often kids going through Peak Height Velocity (10–13 in girls, 12–15 in boys) have overload at their growth plates where the tendons attach (eg heel bone aka Severs Disease) and many other areas (link). Well-meaning parents/coaches/guardians will tell their kid to stretch…which further overloads these bony attachment/growth plate sites (Apophyses) which results in inflammation and swelling (Apophysitis).

You can read a post on injuries in kids going through Peak Growth Phases here: https://medium.com/@TheTennisPhysio/avoiding-injury-during-peak-growth-in-active-kids-5fa1ae2d66f6le

A bit of a poke can’t hurt, right?

The number two exercise people will “research”, is “trigger pointing”, or a poking of hard pointy things into the area of soreness to “release it”.

This adds an extra, and very directed/focal, external and very compressive load onto the tendon, probably the most difficult load for it to tolerate, there will be a short-term release of fluid (like stepping on a wet sponge), however the fluid will come back into the tendon, with a vengeance, with a delayed increase in tightness that is perhaps worse than it was initially.

Can’t stretch it, can’t poke it…. So what do we do then?

So what do we do if our tendons are “tight”, not from shortening, but from having excess fluid in them? Well if you have water in your boat, what do you do?

Let’s use the “tight” hip flexor example, in the tennis player above. He had hip flexor pain with hip extension.

1. Stop further swelling (Plug the hole in the sinking boat)

Identify the cause, in this case it was repetitive hip extension under load. This compresses the tendon against bone, the front of the hip joint, which irritates it and causes swelling. Stretching it, to help, doesn’t. It further compresses the tendon against bone and causes more swelling. There will be an initial reduction in swelling, however there will be a delayed increase in fluid that greatly exceeds the initial reduction. In other words, there will be more swelling and more tightness.

2. Reduce the effusion(swelling) (Bail the boat out)

One: Time. Everyone hates it, in an age of convenience, patients want things better ‘yesterday’. However, with time the swelling will reduce.

Two: The right stimulus. There appears to be a type of exercise that helps push the fluid out of tendons faster, sort of like wringing the water out of a rag rather than ‘stomping on a sponge’, it’s called an Isometric Exercise. It’s when you put load through the tendon without lengthening it.

An isometric exercise provides a ‘happy load’ to a tendon which may have increased fluid content due to an overload injury.

For the hip flexor, this can be done in few ways, here’s a couple:

Push and hold your knee forwards, against a wall, light — only 3–4/10, hold it for a length of time (depending on what works best, trial and error).

Have your foot up on a box, then lift it up and hold, hold it for a length of time (depending on what works best for you, trial and error).

In some circumstances, in some tendons, you will then want to strengthen the tendon up (build up the size of the boat and have a stronger hull) so it can tolerate future loads.

3. Gradual return to activity (+strength and condition) (Start paddling again watching those plugged holes checking for leaks)

Gradually return to the activity that caused the issue in the first place. Maybe continue the isometrics for a time (depending on many things) as well as ongoing strength if you are in a sport that requires more out of that tendon than other sports (eg: hip flexor strength in cyclists).

Why all the “Tight Hip Flexors”?

The hip flexor is made up of a bunch of muscles, iliacus and psoas major and minor (which cross the hip) and rectus femoris (which crosses the hip and the knee, it’s a hip flexor and a knee extensor).

If you have a look from side on, the iliopsoas hip flexor rests on the front of the hip joint.

The hip tendon can be challenged with a compressive load both at end of range hip flexion (knee to chest) and end of range hip extension (leg behind body).

When the hip extends, the hip flexor tendon can ‘rub’ or compress itself onto the front of the hip joint, a rim of bone called the acetabular rim, if it does this too often, with a high load, and little rest, it can cause an external/compressive overload to the tendon, resulting in swelling. Sometimes it can become swollen enough to start flicking over the bone, causing a “snap” or pop, thus it’s termed “Snapping Hip”. The tendon can also be swollen or engorged, but pain free. A little more swelling and it can cause the classic “tight hip flexors”.

In activities/sports involving heavy repetitive hip extension (eg: weight lifting and gymnastics) the repetitive translation forwards (anteriorly) of the femoral head onto the front of the hip joint can overload the anterior and superior labrum (shown in the above picture)

Furthermore , a ‘double whammy of compressive load’ can occur when the hip flexor tendon is pushed up against the front bony part hip joint (high external load) and then is actively flexed in order to stop it from going any further into extension and then change direction (eccentric into concentric contraction of the hip flexor muscles, a high internal load).

Another external load that a hip flexor tendon can experience is when the hip is flexed (knee to chest) such as in a cyclist, the tendon is compressed as it folds back on itself in a small area (under the inguinal ligament), if it’s swollen it’s like trying to fold a inflated animal balloon back on itself (hard), rather than a deflated balloon (much easier).

Balloon Anatomy — On the left: a health happy hip flexor tendon. On the right: a swollen tendon… difficult to fold.

It’d be much easier for the swollen hip flexor to fold back on itself if you could make a twist in the tendon like a balloon animal, but alas, 1) It’d Hurt and 2) It’s Hard to Do.

So this is some sort of new hippy approach to “tight hip flexors” then?

Yes, the all of this is a different approach to “the tight hip flexor” issue that is quite common. However, there are different types of “tightness” that can present, a hip flexor tendon in a cyclist, a desk worker, a footballer and a tennis player all have different loads and all require a different approach when treating “tightness”. So… what will work for you or your patient?

… it depends.

One of the most common painful and “tight” conditions, especially in >40year olds, especially women, is ‘Lateral Hip Pain’ or ‘Gluteal Tendinopathy’. This is an irritated gluteal tendon at the side of the hip. It also causes “tightness” similar to that of the hip flexor tendon. Again, stretches and trigger pointing are innocently and naively administered or recommended by some health professionals. However, once again, these exercises created external compressive load onto the tendon, creating short-term relief, but long-term issues.

Back to that tournament player…..

So, back to our young tennis player with the painful “hip flexor tightness”.

The cause, repetitive and excessive hip extension, possibly compressing the hip flexor tendon against the bone behind it (external/compressive load), as well as an active activation of the hip muscle to slow down the tendon stretch (eccentric contraction) followed by a fast and powerful change of direction.

Double whammy of load, compressing the hip flexor into anterior hip joint, and the femoral head into the anterior hip joint.

All of which are highly challenging for the tendon and unless the tendon has been conditioned and strengthened (aka bigger boat, with a strong hull) it will become irritated and swell (leaky boat) requiring intervention (bailing out).

We’d identify the load (court surface, tournament schedule, type of game (baseliner vs serve/volley)), calm the tendon down (isometric exercises, rest, soft-tissue around (but not on) the area, gradually rebuild the strength and condition the structures to tolerate the high loads again.