When Do We Stop? When Can We Train Around It? When Do We Refer Out?

A trainer's guide to the "I tweaked my hamstring" Monday

By Dr. Rob Letizia, PT, DPT, Owner, Spectrum Therapeutics, Wayne, NJ

_____________________________________________________________________________________________

1. The Monday morning problem

Your client played pickleball Saturday. They were lunging out wide for a drop shot, the front leg reaching and the knee straightening fast, and they felt a grab high in the back of the thigh. They finished the game. They rested Sunday. Now it's Monday at 7 a.m., they're standing in front of you, and they say it:

"I tweaked my hamstring."

You have about thirty seconds to decide what today looks like, and even experienced coaches tend to fall back on one of two defaults. One is "Let's just work around it", which sometimes means loading a real injury. The other is "You should probably see someone", which is fine, but it also sends away a client who was entirely safe to train, and it teaches them that you can't help when something hurts.

Neither default is a plan. What follows is a plan: four questions you ask before you touch the programming, a short list of signs that end the session, what a physical therapist is looking for when you refer, how to rebuild the leg in stages when none of those signs are present, where your scope ends, and how to stay involved after a referral. None of it asks you to diagnose anything. It's the reasoning I'd want from any coach I refer to, or take referrals from.

The hamstring is the example because it's the one you'll see most. But hold onto it, because at the end we'll run the exact same framework on a completely different client.

_________________________________________________________________________

2. Four questions and a set of load checks

Before you touch the programming, get four answers from the conversation, then run a few load checks. The whole thing takes about five minutes, and it decides the rest of the session.

Question 1: Mechanism. What exactly was the body doing when it happened?

You want the movement, not the sport. "Playing pickleball" tells you nothing. "Reaching for a ball with my leg out straight and I felt it grab" tells you a lot. A hamstring that gets hurt while it's being stretched under load, the way it does in a long lunge or in the late swing phase of a sprint, behaves differently from one that just felt tight after a long walk.

Also listen for how sudden it was. "It got tighter and tighter over the game" is a different story from "one moment I was fine, the next I wasn't."

Say it to the client: "Walk me through the exact moment. What was your leg doing, and what did you feel?"

Question 2: Pain behavior. What makes it worse, and what makes it better?

You're looking for a pattern. Does it hurt when they sit on a hard chair? When they bend forward to tie a shoe? When they walk fast? Does it ease with gentle movement, or does movement make it steadily worse?

Pain that has a clear, mechanical pattern (worse with this, better with that) is usually the reassuring kind. Pain with no pattern, pain that's there no matter what they do, or pain that's worst at rest is the kind you pay attention to.

Say it to the client: "What makes it worse? And is there anything that makes it feel better?"

Question 3: Load tolerance. What can they actually do right now?

This is where you stop listening and start watching. Start with everyday load:

• Walking. Normal gait, or a shortened stride on that side?
• Stairs. Up and down a flight without favoring the leg?
• Single-leg stance. Does it look like the other side?

A client who can't walk normally isn't a client you're training today. That's section 3.

Say it to the client: "Before we do anything, I just want to watch you move. Walk to the wall and back for me."

 

The load checks: what will the hamstring tolerate?

If everyday load is clean, find out what the hamstring itself tolerates. These are the same movements you already program. You're just using them as a gauge before you load them. Always compare against the good side first.

• Bent-knee bridge. Two legs, then single-leg. Knees well bent keeps the hamstring working at a short length. Compare effort, pain, and any cramping side to side.
• Long-lever bridge. Walk the heels out until the knees are nearly straight, and repeat. Now the hamstring is working at a longer length. This is often where a mild strain shows itself when the bent-knee version was fine.
• Unloaded hinge. A bodyweight RDL pattern, slowly. Note where it first bites compared with the other side. This isn't a flexibility test. Stop at the first symptom, not at end range.

The rules are the same as in training: stop at anything sharp, and stay inside the pain ceiling in section 5. You're not trying to find out what is injured. That's the clinician's question. You're finding out where training can start.

Reading the checks:

• Bent-knee bridge painful, or clearly weaker than the other side: start at Stage 1.
• Bent-knee bridge fine, but the long-lever bridge or the hinge provokes it: start at Stage 2, and keep out of long-length work for now
• All three comfortable and close to symmetrical: start at Stage 3. Speed still has to be earned in Stage 4.
• ·Anything that feels worse than the story suggested, or any red flag, puts you in section 3.

Say it to the client: "I'm going to put that leg through a few movements you already know, and compare it with the good side. This isn't me diagnosing anything. It's me finding where we can start today."

 

Question 4: Trajectory. Better, worse, or flat since it happened?

This is the question trainers skip, and it's the one that tells you the most. An injury that was bad Saturday, better Sunday and better again Monday is healing. An injury that was mild Saturday and is worse Monday, after a day of rest, is telling you something is going on that rest didn't settle.

Flat is the middle ground. Not getting better after a couple of days of sensible activity is worth noting, even if it isn't an alarm.

Say it to the client: "Compared with Saturday, is it better, worse, or about the same?"

3. Refer now, not later

Here's the short list. If any one of these is present, the session ends and the client gets looked at by a licensed clinician before their next session. Not "keep an eye on it." Not "let's see how next week goes." Before the next session, and for two of them (deep pain at the sit bone with a pop, and a swollen, warm calf) the same day.

• They can't bear weight or walk normally. A limp that doesn't go away as they warm up is a limp.
• An audible pop with immediate loss of function. They heard or felt something give, and the leg stopped working right at that moment.
• A gap or a divot in the muscle. Something that looks or feels different from the other leg: a dip, a lump, a change in contour.
• Deep pain right at the sit bone. Pain at the very top of the hamstring, where it attaches to the pelvis, is a different problem from pain in the middle of the muscle. With a sudden pop, immediate weakness, trouble walking, bruising that develops quickly, or a gap you can feel, treat it as a possible tear of the tendon off the bone (a proximal hamstring avulsion). Stop the session and arrange same-day assessment by a sports-medicine physician, an orthopedic clinician, or a physical therapist experienced with acute hamstring injuries. Don't wait for the next session: these injuries do worse when they're recognized late. If they can't bear weight, the leg looks deformed, nerve symptoms are getting worse, or the pain is severe and not controlled, that's urgent or emergency care.
• Bruising that spreads over the next day or two. Bruising that tracks down the back of the thigh toward the knee means there was real bleeding inside the tissue.
• Numbness, tingling or weakness down the leg. That's a nerve talking, not a muscle, and it needs a clinician to sort out.
• A calf that's swollen and warm. This isn't a hamstring sign at all, and that's the point. A swollen, warm, tender calf can mean a blood clot, and it needs to be seen the same day.
• Pain that wakes them at night. Musculoskeletal pain usually settles when you take the load off it. Pain that wakes someone up is outside the normal pattern.

A few notes on using this list well.

Don't negotiate with it. You have good judgment, and that's exactly why it stays out of this list. A red-flag list only works if it's binary. The moment it becomes "well, it's only a little bruising," it stops protecting anyone, including you.

Ask, don't just look. Clients rarely volunteer these. "Did you hear anything when it happened?" "Any numbness or tingling down the leg?" "Has it been waking you up?" Fold them into the four questions.

Refer to a specific place. "Go see someone" is a shrug. "I want a physical therapist to look at this before we train it. Here's who I'd send you to" is a professional recommendation. Know who you'd send people to before the Monday it happens.

Say it to the client: "I'm not going to train this today, and here's why. You heard a pop and the bruising has spread since Saturday. That's exactly the kind of thing I want a clinician to look at first. It's not me being cautious for the sake of it. It's the rule I use for everyone, and you'll be back in here faster for it."

4. What I'm looking for when they see me

Some of this will look familiar. Your load checks overlap with parts of my exam, and that's deliberate. The difference is the question: I'm using those movements, along with hands-on and nerve testing, to work out what's injured. You're using them to decide where training starts. Same movements, different job. The hands-on part, and the conclusion at the end of it, stay on my side of the referral.

It's still worth knowing how I think it through. It tells you why I'll ask you to hold some things back and keep others going, and it sharpens the part you own: watching, asking, and adjusting load.

Here's how I think through a hamstring, in the order I do it.

The story comes first. Most of the answer is in the history, which is why your four questions matter so much. I want the exact movement, how sudden it was, and what they could and couldn't do in the first hour. Hamstrings tend to get hurt in one of two ways. One is at speed, usually during fast running, when the muscle is working hard to slow the leg down. The other is at a long stretch, the way a lunge for a drop shot or a high kick loads it. Stretch-type injuries often sit higher up, closer to the sit bone, and they tend to take longer to come back than people expect, even when they don't feel dramatic on day one. That single detail changes how patient I'll be.

Then I find where it lives. I'm looking for the most tender spot and how big the sore area is, and especially how close it is to the sit bone. Generally, the closer to the attachment and the larger the area involved, the more cautious the plan.

Then I see what provokes it. I'm separating two things: does it hurt when the muscle contracts, or when it's lengthened, or only when you ask it to do both at once? I check that at different knee and hip angles, because a hamstring that's comfortable working at a short length can still be irritable at a long one. That's the most useful finding for you, because it tells us where training can start.

Then I compare sides. How strong is the injured leg against the good one, and how does that change with the position? A leg that's strong but sore is a different problem from one that's genuinely weak.

Then I rule things out. The sciatic nerve runs right alongside the hamstring, and back-of-thigh pain isn't always muscle. Irritated nerves and referred pain from the lower back can feel very similar, and they need a different plan. Sorting that out, and ruling out the red flags in section 3, is squarely a clinician's call.

What each finding means for training. This is the part worth remembering:

• Pain on stretch, not on contraction? We can usually start strengthening early, at short muscle lengths, and hold off on long-length work.
• Pain on contraction at a long length? Keep the loading in the middle and short ranges until that settles.
• A clear strength gap between sides? Closing that gap becomes the main job, not the soreness.
• Nerve involvement? Different plan altogether, and I'll tell you exactly what to avoid.

You'll notice none of that is a label. I'm not telling you "it's a grade 2" and leaving you to guess what to do with it. I'm telling you what it tolerates, and that's something you can train.

5. When you can train around it

Now the more common case. They walk normally. No pop, no gap, no bruising to speak of, no nerve symptoms, nothing waking them up. It's sore, it's better than Saturday, and they want to train.

This is where you earn your keep, because not training is not the safe answer here. Rest makes a client feel careful. It doesn't make the tissue stronger. A client who sits out a week for a mild strain comes back deconditioned, nervous, and just as vulnerable to doing it again.

Two things make that work: a rule that governs every session, and a progression that tells you what comes next.

The rule I'd hand a trainer

This is the part that replaces "push through it":

A pain ceiling you actually hold to, plus a 24-hour check.

A clear caveat first: this is a coaching heuristic for managing load. It isn't a diagnosis, and it isn't a research-proven cutoff. The right threshold depends on the person, the activity and how far along the injury is. As a working rule, though:

During the session, exercise-related pain stays mild and stable, generally no more than about 3 out of 10. That's something they notice but that doesn't change how they move. No sharp pain, no change in mechanics, and no pain that keeps climbing as the session goes on. If an exercise breaks any of that, the exercise changes: shorter range, lighter load, slower speed, less volume, or out entirely. Not "one more set." Changes.

Then watch the next 24 hours, not just the session. By the next morning, symptoms should be back to baseline, meaning where they were before the session. If pain or stiffness is clearly worse the next day, you did too much. Reduce the load, range, speed or volume next time and reassess. If it's getting steadily worse from session to session despite that, it goes back to section 3. That's a referral, not a programming problem.

The reason this works is that it takes the judgment out of the moment. Your client doesn't have to decide whether they're being tough or being stupid. They just report a number and a next-morning check, and the program responds.

Say it to the client: "Here's how today works. We're going to train, just not that leg the way you're used to. If anything we do pushes it past about a 3 out of 10, or it turns sharp, tell me and we change it. Not 'I'll finish the set.' Tell me. Then notice how it feels tonight and getting out of bed tomorrow, compared with how it felt when you walked in today. That tells us whether we got it right."

 

The progression: four stages

This is roughly how I'd rebuild a hamstring myself, written for the part you run. Two principles sit underneath it. First, move up by criteria, not by the calendar. A stage ends when the client meets the signal to move on, not when a week has passed. Second, the pain ceiling and the 24-hour check apply at every stage. They're how you know whether a step up was the right call.

Not everyone starts at Stage 1. The load checks in section 2 tell you where to begin.

If a clinician is involved, their plan wins. Use this to understand it and to fill in the sessions between visits, not to overrule it.

One programming note that runs through all four stages: the hamstring does two jobs, extending the hip and bending the knee. Train both. A plan that's all hinges or all curls leaves half the muscle's job untrained.

Stage 1: Settle it down and keep them training.
The goal is to keep the client strong everywhere else while the leg calms down.

• Train the other leg as normal. Cross-education is real, and so is the psychology: they leave having trained, not having been benched.
• Upper body, trunk, and anything that doesn't put a stretch or a hard contraction through the back of that thigh.
• Isometric holds at a comfortable angle and a moderate effort: a bent-knee bridge hold, or a heel dig into the floor. Longer holds rather than hard ones.
• Conditioning that doesn't reproduce it: bike at light resistance, upper-body ergometer, pool if it's comfortable.
• Leave alone: anything fast, anything long, and anything that stretches the hamstring under load. That means sprinting, jumping, deep hinges, and anything that looks like the movement that hurt it.
• Move on when: they walk normally, daily life is comfortable, and the holds feel easy at a moderate effort with a clean next morning.

Say it to the client: "This week is about keeping everything else strong and letting that leg calm down. You're still training. We're just choosing what that leg does."

 

Stage 2: Build strength in the middle of the range.
The goal is to start loading the hamstring properly, in positions it tolerates.

• Hip-dominant: bridges progressing from two legs to one and from holds to slow reps, then a loaded hinge through a short range, stopping well before the stretch
• Knee-dominant: machine or band curls with a slow, controlled lowering.
• Step-ups and split squats if they're comfortable.
• Slow tempo throughout. At this stage, controlled speed is part of the dose.
• Move on when: these feel solid at a meaningful load, the next-morning check stays clean, and the two sides feel close in effort.

Stage 3: Build strength at length.
The goal is to make the hamstring strong where it got hurt: at a long length, while it's lengthening under load. This is the stage that's most often skipped, and skipping it is how people end up doing the same injury twice.

• Hip-dominant: RDLs progressing toward full range and heavier loads, then single-leg RDLs.
• Knee-dominant: slider or ball curls with the emphasis on the eccentric.
• Long-length eccentric work, like an assisted Nordic, once everything else here is comfortable.
• Move on when: long-length work is comfortable at real loads, strength feels even side to side, and the 24-hour check stays clean.

Say it to the client: "This is the part most people skip, and it's the part that keeps you from doing this again. We're making that hamstring strong in exactly the position it got hurt."

Stage 4: Speed, then the sport.
The goal is to bring back speed, then the specific movement that caused the injury.

• Build sprint exposure progressively: easy running, then submaximal strides, increasing speed only as each step stays symptom-free both during and the next morning. Top speed is the last thing to come back.
• Add change of direction and deceleration.
• Rebuild the exact movement that hurt it. For our pickleball player, that's the wide reaching lunge, starting slow and short, and building toward game speed and full reach.
• Ready to play when: they can do the sport's hardest movements at full speed and full reach, with no symptoms during or after. If a clinician managed the injury, the green light for full sport is theirs to give.

Stepping back is part of the plan. If the next morning is clearly worse, drop back to the previous stage's work for a few sessions, then try again. That's not failure. It's the plan working. If they keep getting worse despite stepping back, it's no longer a programming problem. It goes back to section 3.

6. Staying in scope

You know most of this already. It's here because it's the part that protects you, and the part that makes clinicians comfortable sending clients your way.

Within your scope, you can:

• Ask the four questions and the red-flag questions.
• Run load checks to decide where training starts.
• Watch how someone walks, climbs stairs and stands on one leg.
• Compare the two sides for symmetry and movement quality.
• Observe how pain responds to load: what provokes it, what doesn't, and what happens the next day.
• Modify the program in response to all of the above.
• Progress training through the stages using the pain ceiling and the 24-hour check.
• Coordinate with the treating clinician and carry out their plan between visits.

Outside your scope, you can't:

• Grade a strain. "It's just a grade 1" is a diagnosis. You don't know that, and neither does anyone else without examining it.
• Use hands-on, resisted or nerve testing to work out what's injured. The load checks tell you what it tolerates. Working out what it is belongs to the clinician.
• Rule out nerve involvement, a tendon injury at the sit bone, or anything else on the red-flag list.
• Clear anyone to return to sport or to full training after an injury.

Saying that line out loud makes you more credible with clients, not less. The trainer who says "That's a question for a physical therapist, and here's who I'd send you to" sounds like a professional who knows where the edges are. The trainer who guesses sounds confident right up until they're wrong, and when they're wrong, the client remembers.

There's a practical benefit too. A trainer who refers well builds a relationship with the clinicians they refer to. Those clinicians send patients back to you when rehab is done and they're ready for a real program. That's a two-way street you want to be on.

Say it to the client: "What I can tell you is how your leg is moving and how it's responding to load. What I can't tell you is exactly what's injured or how bad it is. That's a clinician's call, and I'd rather get that right than guess."

7. How to hand off, and stay in the picture

A referral shouldn't be the end of your involvement. Done well, it's the start of a partnership, and the client gets better faster because of it.

Write it down before they leave. Two minutes of notes makes you the most useful person in the referral chain:

• The date and the exact mechanism, in the client's words.
• The answers to the four questions.
• What they could and couldn't do when you watched them move.
•  What you've done with them since, and how the next mornings went.

Clinicians rarely get that kind of detail. It speeds up the first visit.

Tell the client what happens next. Who you'd send them to, why, and what that first visit is for. A client who knows what to expect actually books the appointment.

Ask to stay in the loop. The clinician can't talk to you about the client without the client's permission, so ask the client to give it. Then ask the clinician three things:

• What should I avoid for now?
• What should I keep training?
• Which stage are we in, and what would tell you they're ready for the next one?

Pick up where the clinician leaves off. When they're discharged from therapy, most clients aren't ready for full training yet. They're ready for a coach. That's you, and it's where Stage 3 and Stage 4 happen for a lot of people.

Say it to the client: "I want you to see a physical therapist about this, and I'd like to stay involved while you do. Would you be OK with me talking to them? That way what we do in here matches what they're doing, and you're not getting two different plans."

8. The everyday-client translation

Now forget the pickleball court.

Your next client is a 52-year-old who doesn't play any sport. He comes in Tuesday and says, "I tweaked my back lifting my suitcase out of the trunk this weekend."

It feels like a completely different situation. It isn't. Run the identical framework.

Mechanism. What was he doing? Bent and twisted with a heavy bag at arm's length is a very ordinary way to strain a back. Was it sudden, or did it build?

Pain behavior. What makes it worse (sitting, bending, coughing) and what makes it better (walking, lying down)? Is there a clear pattern?

Load tolerance. Can he walk normally? Get up from a chair? Bend a little and come back up?

Trajectory. Better, worse, or flat since the weekend?

Then the red-flag list, with a few swaps for a back: numbness or tingling down one or both legs, weakness in a leg or foot, any change in bladder or bowel control or numbness in the groin or saddle area (that one is an emergency room, today), pain that wakes him at night, or feeling generally unwell with a fever alongside the back pain. Any one of those and he's seen before he's trained.

If none of it is present, you're back in section 5. Train what doesn't hurt, keep him moving, hold the same pain ceiling, check over the next 24 hours, and build back up by stages. Same scope, same honesty about where it ends.

That's the whole point. The weekend warrior and the guy with the suitcase aren't two different problems. They're the same four questions, the same red-flag discipline, the same pain ceiling. Once you've got the framework, you don't need to know every injury. You need to know how to ask.

The bottom line

When a client walks in hurt, you have three answers available, and each one has a trigger.

Stop when any red flag is present. No negotiation, no "let's see."

Refer when a red flag is present, or when a sensible, pain-limited program still isn't moving things in the right direction after a week or two. Refer to a specific person, and say why.

Train around it when the four questions come back clean. That's most of the time, and it's the answer that keeps your client strong, confident, and coming back.

What you shouldn't do is guess, or default to rest because it feels safe. A clear process is what makes you the trainer a client trusts with their Monday-morning hamstring. And if you refer well, a physical therapist will be glad to hand them back to you.

___________________________________________________________________________________________

Dr. Rob Letizia, PT, DPT is the owner of Spectrum Therapeutics in Wayne, New Jersey, a single-provider orthopedic clinic where every session is one-on-one with a doctor of physical therapy. He treats sports injuries, post-surgical rehabilitation and vestibular disorders, and works with athletes and weekend warriors on sports injury rehab and return to training.

This article is general education for fitness professionals and is not medical advice or a substitute for individual evaluation. Trainers should work within their scope of practice and refer to a licensed clinician when the signs above are present.