Exercise prescription. 10 minute read.
The FITT principle for exercise prescription in rehab, with worked examples
The FITT principle is a checklist for writing an exercise dose: frequency (how often), intensity (how hard), time (how long) and type (which exercise). The extended version, FITT-VP, adds volume (how much in total) and progression (when and how to do more). Set all six for each exercise in a home program and the patient knows what to do on their own, and so does the next clinician who reads your note.
Below, each letter is covered as physical therapists and physios use it in clinic. After that come four ways to set intensity without a 1RM test, three worked examples, and where FITT sits when you write a home exercise program (HEP).
What does the FITT principle stand for?
| Letter | The question it answers | What it can look like in a home program |
|---|---|---|
| Frequency | How often? | 3 days a week, or twice a day |
| Intensity | How hard? | Stop each set with 2 or 3 good reps left; 5 or 6 out of 10 effort |
| Time | How long? | 30 s holds, 2 sets of 10, 15 minutes of walking |
| Type | Which exercise? | Sit to stand, a seated hamstring stretch, brisk walking |
| Volume | How much in total? | Sets x reps x sessions per week, or minutes per week |
| Progression | When and how to do more? | "When 2 sets of 12 feel easy two sessions running, lower the seat" |
For strength work, sets and reps do the job that minutes do for walking, so many physios write them under time or volume. Where you put them matters less than writing them down.
The framework is best known from American College of Sports Medicine (ACSM) guidance. Its 2011 position stand by Garber and colleagues gives a recommendation for each letter across aerobic, strength, stretching and balance training. Rehab researchers use the same frame: Milani and colleagues, writing on cardiac rehab, recommend aligning prescription with the FITT-VP model.
One caution before you borrow any number from ACSM: the position stands were written for apparently healthy adults. Your patient's ceiling depends on the irritability of the problem and the stage of tissue healing. After surgery, the surgeon's protocol decides it.
Frequency: how often
Frequency is the easy one. The Garber stand recommends strength work for each major muscle group on 2 to 3 days a week and flexibility work on at least 2. Balance and coordination work also gets 2 to 3 days. The World Health Organization (WHO) 2020 guidelines ask adults to do muscle-strengthening activity on 2 or more days a week. For older adults they add varied multicomponent activity that emphasizes functional balance and strength training on 3 or more days a week.
Rehab frequency often looks nothing like a gym plan. Physios tend to give early range-of-motion work once or several times a day, in short bouts. That comes from common practice, not from ACSM, whose stands leave this kind of work out. Harder strength work usually goes on 2 or 3 days a week, often with a rest day in between, which fits the ACSM range above.
Whatever you choose, tie it to a day and a time. "3 times a week" is easier to follow when it reads "Monday, Wednesday and Friday after breakfast", and the adherence guide covers why.
Intensity: how hard should rehab exercise feel?
Intensity is easy to leave off a handout. "2 sets of 10" says nothing about whether those 10 should feel easy or close to the limit. Morrison and colleagues found the same gap in the research: in an umbrella review of 25 systematic reviews of exercise for older adults, only 6 reported intensity completely, against 23 for frequency.
Most patients will not have a one-repetition maximum (1RM) tested, and a home program cannot rely on one. These four methods work without it.
Rating of perceived exertion (RPE)
RPE asks the patient how hard the effort feels on a number scale. The scales come from Gunnar Borg's work on perceived exertion. A 0 to 10 version is simple to use in a home program, and WHO uses the same kind of scale to describe effort: moderate activity is usually a 5 or 6 out of 10, and vigorous activity a 7 or 8.
RPE is repeatable, but it is not a precise stand-in for a percentage of maximum. Bove and colleagues checked this in JOSPT, asking adults with or without knee problems to rate knee extension exercise from 0 to 10. Test-retest reliability was excellent. Agreement between RPE and percentage of 1RM was poor, though, especially in the ranges usually used for strengthening. Use RPE to keep the patient's effort consistent from session to session, and to adjust the load, rather than to hit an exact percentage.
Reps in reserve (RIR)
Reps in reserve is the number of good reps the patient still had in the tank when they stopped the set. Zourdos and colleagues published a scale built on it, in which an RPE of 10 means no reps left and 9 means one left. They concluded it is a practical way to regulate daily training load. It was tested in 29 young experienced and novice lifters doing the squat, not in rehab patients, so expect a patient's first estimates to be rough.
In a home program it translates into one plain line: "Stop each set when you could do about 2 or 3 more good reps." The load then adjusts itself: fewer reps on a bad day, more on a good one. That is a practical use of the scale rather than something the study tested in patients.
The talk test
The talk test uses how comfortably someone can speak as a gauge of aerobic effort. Milani and colleagues describe three stages. If the patient can still talk comfortably, they are usually below the first ventilatory threshold, the point where breathing first starts to pick up noticeably. When talking becomes somewhat uncomfortable, they have moved above it, and when they cannot talk comfortably at all, they are above the second threshold and working hard.
It needs no equipment and suits walking programs well. Our brisk walking page gives patients a version they can check alone: breathing quicker and feeling warm, but still able to talk.
Heart rate and the Karvonen method
Heart rate targets suit patients who wear a watch or heart rate strap and want a number. The Karvonen method takes a percentage of heart rate reserve (the gap between maximum and resting heart rate) and adds resting heart rate back on. Our target heart rate calculator does the arithmetic and shows the zones.
Two limits apply. First, maximum heart rate is estimated from age. Milani and colleagues point out that these equations rest on age and resting values rather than the person's actual response to exercise. Second, heart rate is a poor guide for people on beta blockers, whose heart rate response is blunted. For them, RPE or the talk test is the usual alternative, and anyone with heart disease should have their intensity set by their medical team.
Time: how long
For aerobic work, time is minutes per session. The Garber stand recommends at least 30 minutes of moderate activity on at least 5 days a week (150 minutes or more a week), or at least 20 minutes of vigorous activity on at least 3 days (75 minutes or more). WHO 2020 sets a range of 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity a week.
WHO also dropped the old rule that activity only counted in bouts of at least 10 minutes. Bouts of any length now count. That helps rehab patients who can only manage a few minutes at a time, and both documents make the same point: some activity is better than none, even below the targets.
For stretching, time is the hold. Garber and colleagues recommend 60 seconds in total per stretch, and that total can be built from shorter holds. For strength work, time is sets, reps, hold time at the top and sometimes the speed of the lowering phase.
Type: which exercise
Type is where your assessment comes in. Choose the exercise that works on the finding you are treating, then choose the version this patient can do well today, for example seated rather than standing, or with a hand on support. A patient who struggles to get up from a chair gets sit to stand before a gym leg press, because it trains the task itself.
The home exercise program guide has a short set of filters for choosing exercises, starting with whether the patient can do it correctly today and at home with what they have.
Volume and progression: the VP in FITT-VP
Volume is the total dose: sets x reps x sessions a week for strength, or minutes a week for walking. It lets you compare two programs that look different on paper. Three sessions of 2 sets of 10 is 60 reps a week, and so is two sessions of 3 sets of 10.
Some rehab research now reports dose as volume. In a 2026 JOSPT dose-response meta-analysis of 20 randomized trials in knee osteoarthritis, Núñez-Cortés and colleagues found moderate-intensity resistance exercise was linked with the largest estimated gains in function. They counted volume as total repetitions over the program. Pain, function and strength each showed their largest estimated effect at a different volume.
The certainty of evidence was low to very low, so treat it as a direction, not a target. Our knee osteoarthritis program shows how a progression looks in practice.
On progression, research gives you the least help. None of the 25 reviews in the Morrison umbrella review reported it completely. The guidelines do agree on going slowly. Garber and colleagues write that building up intensity and volume bit by bit may lower the risks of exercise. WHO advises starting small and increasing how often, how hard and how long over time.
The 2009 ACSM stand is more specific for strength. When the person manages 1 or 2 reps over the target, it suggests adding 2 to 10% to the load.
Most patients have no dumbbells at home, so the harder step tends to be a lower seat, a firmer band, a slower lowering phase or a single-leg version. Many physios change one letter at a time, often adding reps or minutes before raising intensity, so a flare can be traced to a single change. Trials have not tested this; it is common practice. Regression works the same way backwards: take one letter back a step and leave it there until the patient settles.
Worked examples: FITT for a strength exercise, a stretch and walking
The three examples below use invented patients to show how the letters fit together. The numbers are general starting ranges, not a prescription. Your own numbers come from your assessment and change with the patient's response. If you are a patient reading this, your physio will adjust the dose for you.
Strength: sit to stand for knee osteoarthritis
Mr. D, 67, knee osteoarthritis, finds getting out of low chairs hard. Sit to stand from a sturdy dining chair with its back against a wall and a firm cushion on the seat.
| FITT-VP | What you write |
|---|---|
| Frequency | 3 days a week, Monday, Wednesday and Friday after breakfast |
| Intensity | Stop each set with about 3 good reps left. Knee ache during the set is fine if it stays at 3 out of 10 or below, has settled by the next morning, the knee is no more swollen the next day and the ache is not building from week to week |
| Time | 1 set of 10 to 15 at first, building to 3 sets, arms held out in front, a short rest between sets |
| Type | Sit to stand, lowering slowly onto the seat |
| Volume | 30 reps a week at the start, up to 135 |
| Progression | Once 3 sets of 15 feel easy on 2 sessions running, take the cushion off. Later, move to a bodyweight squat |
The sit to stand page gives a common starting dose of 2 to 3 sets of 5 to 10, once a day or on most days, while the movement is being learned. Mr. D can already do 10 or more with control, so here it is worked as strength training, which the ACSM stands put on 2 to 3 days a week. ACSM 2009 gives 8 to 12 reps for most people new to strength training, with a load that makes those reps hard. Garber and colleagues suggest that middle-aged and older adults who are new to it start lighter, with a load they can move 10 to 15 times, and note that 1 set can be enough at first. Stopping with about 3 reps left keeps the effort moderate.
The 3 out of 10 ache limit is a cautious starting choice, not a research figure. The pain-monitoring model in tendon research allowed up to 5, as the home exercise program guide explains.
Regression is built in too: a higher seat, or sit to stand using the armrests, if the knee flares or the patient cannot stand without a push from the hands. If Mr. D has high blood pressure, he should breathe steadily through every repetition and never hold his breath.
Stretch: seated hamstring stretch
Ms. L, 54, tight hamstrings that limit bending at the hips, no leg symptoms. Seated hamstring stretch on a kitchen chair.
| FITT-VP | What you write |
|---|---|
| Frequency | Most days, and at least 2 days a week |
| Intensity | Lean until a gentle, even pull at the back of the thigh. Not pain, and never tingling down the leg |
| Time | 3 holds of 20 s or 2 holds of 30 s on each leg |
| Type | Seated version; the supine hamstring stretch if lying down suits better |
| Volume | 60 s per leg per session |
| Progression | Consistency first. If range is the goal, measure it at the review the same way each time, for example a straight leg raise angle |
The 60 seconds per leg comes straight from the Garber recommendation. Stretching progresses less visibly than strength, which is why a measurement at the review helps both of you.
Walking: brisk walking after a long lay-off
Mrs. P, 60, has been inactive for months after a period of illness, now cleared by her doctor to build up activity. Brisk walking on a flat route near home.
| FITT-VP | What you write |
|---|---|
| Frequency | 5 days a week |
| Intensity | Breathing quicker and feeling warm, but still able to talk. About 5 or 6 out of 10 effort |
| Time | 10 minutes, including a few minutes of slow walking at each end |
| Type | Brisk walking on a flat, well-lit route |
| Volume | 50 minutes a week to start |
| Progression | Add a few minutes to each walk every week or two, adding time before speed. Long-term aim: 150 minutes or more a week |
The long-term aim is the WHO figure, and every minute on the way there counts. If Mrs. P has a heart or lung condition or high blood pressure, her doctor or physio should set how much and how fast she walks before she starts.
How FITT fits into a home exercise program
A home program is a FITT prescription the patient carries out alone. Any letter you leave out, the patient guesses. In the Morrison review, the letters most often incomplete were intensity and progression. A handout can have the same gap.
Trials have the same problem. The Consensus on Exercise Reporting Template (CERT), developed by an international panel of exercise experts through a Delphi study and published in Physical Therapy, is a 16-item checklist that includes dosage and tailoring. When Slade and colleagues applied it to 20 musculoskeletal trials, 60% of the exercise descriptions were missing information for at least half of the CERT items. If published trials leave the dose unclear, a rushed home program handout will too.
A simple habit fixes most of it. For each exercise, write one line per letter, as in the tables above, and put the same numbers in your clinical note. The SOAP notes guide shows where the dose goes in the plan. For the rest of the process, from choosing how many exercises to booking the review, read how to write a home exercise program.
In PocketPhysio you pick the exercises, set reps, sets and hold times for each one, and can write a cue in your own words. Put the intensity line and the progression rule in that cue. Each exercise in it has its own video and voice guide. You can send it as a link, by SMS or email, or on WhatsApp, and the patient can also open it in the Pocket Physio Care app.
When to stop, whatever the dose says
A dose is a plan, and some symptoms override it. Teach every patient on a walking or strength program to stop and get help for these:
- Chest pain or pressure, dizziness or feeling faint, a racing or irregular heartbeat, or being far more out of breath than the effort should cause.
- Your calf or thigh becomes swollen, warm, tender, red or darker than usual, or has a throbbing or cramping pain that feels different from normal muscle ache. Stop and get medical advice the same day, as this can be a blood clot. If you are also short of breath or have chest pain, call emergency services.
- Pins and needles, numbness or weakness in an arm or leg that does not go away after you stop. Get medical advice the same day. If one side of your face or body suddenly goes numb or weak, or your speech becomes slurred or muddled, call emergency services, even if it goes away.
- Sharp pain during an exercise, or pain or swelling that is clearly worse the next day. Stop that exercise and check with your physio before you do it again.
If chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack. If it eases quickly and none of these happen, get medical advice the same day, and do not exercise again until you have been checked. If you faint while exercising, call emergency services, even if you feel fine again quickly.
After surgery, the dose comes from the surgeon's instructions or the local protocol, not from a guideline written for healthy adults. For heart and lung conditions, intensity is the medical team's call.
The short version
The FITT principle turns "do some exercises" into a dose the patient can follow: frequency, intensity, time and type. Add volume and progression and you have FITT-VP, which also tells the patient how much in total and when to do more. Intensity is easy to leave out, so give the patient a way to judge it, such as reps in reserve or a 0 to 10 effort scale. Write the progression rule down and put the same numbers in your note.
References
- Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Medicine and Science in Sports and Exercise. 2011;43(7):1334-1359. doi:10.1249/MSS.0b013e318213fefb
- Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine. 2020;54(24):1451-1462. doi:10.1136/bjsports-2020-102955
- American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Medicine and Science in Sports and Exercise. 2009;41(3):687-708. doi:10.1249/MSS.0b013e3181915670
- Milani JGPO, Milani M, Verboven K, Cipriano G Jr, Hansen D. Exercise intensity prescription in cardiovascular rehabilitation: bridging the gap between best evidence and clinical practice. Frontiers in Cardiovascular Medicine. 2024;11:1380639. doi:10.3389/fcvm.2024.1380639
- Borg GA. Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise. 1982;14(5):377-381. doi:10.1249/00005768-198205000-00012
- Bove AM, Lynch AD, DePaul SM, Terhorst L, Irrgang JJ, Fitzgerald GK. Test-retest reliability of rating of perceived exertion and agreement with 1-repetition maximum in adults. Journal of Orthopaedic and Sports Physical Therapy. 2016;46(9):768-774. doi:10.2519/jospt.2016.6498
- Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research. 2016;30(1):267-275. doi:10.1519/JSC.0000000000001049
- Núñez-Cortés R, Suso-Martí L, Tur-Boned A, et al. Tailoring resistance exercise for knee osteoarthritis: an intervention systematic review with dose-response meta-analysis of the effects of intensity and volume. Journal of Orthopaedic and Sports Physical Therapy. 2026;56(9):585-595. doi:10.2519/jospt.2026.13477
- Morrison RT, Mannion L, MacDonncha C. Attention to principles of training and exercise prescription in systematic reviews of exercise for functional performance in older adults: an umbrella review. Systematic Reviews. 2026;15(1):72. doi:10.1186/s13643-025-03049-x
- Slade SC, Dionne CE, Underwood M, et al. Consensus on Exercise Reporting Template (CERT): modified Delphi study. Physical Therapy. 2016;96(10):1514-1524. doi:10.2522/ptj.20150668
- Slade SC, Finnegan S, Dionne CE, Underwood M, Buchbinder R. The Consensus on Exercise Reporting Template (CERT) applied to exercise interventions in musculoskeletal trials demonstrated good rater agreement and incomplete reporting. Journal of Clinical Epidemiology. 2018;103:120-130. doi:10.1016/j.jclinepi.2018.07.009
Written and checked by the PocketPhysio editorial team. Last updated 2026-09-28.