4-Day Workout Split: Who Is It For and How Do You Build One?

A 4-day workout split divides the week's weight training into four different workouts. It is a natural choice when you can train four days per week consistently and want each session in your workout routine to focus on different muscle groups.

This article looks at what research says about workout splits, how many sets you should do per week, how to schedule a four-day training plan sensibly, and the potential challenges of a 4-day workout split. At the end, you will find four ready-made workout plan templates, two of which are written out exercise by exercise with sets and reps.

One thing is worth saying right away: choosing the split is only half the battle. The split itself does not determine your results. Based on the research, weekly training volume per muscle group, sufficient loading, training frequency, proper recovery, and progressive overload matter more than what the split is called. A well-designed 4-day workout split makes these fundamentals easier to organize, which is exactly why this training style is so popular.

4-Day Workout Split in Short

• The Upper/Lower Split is the most practical default for many intermediate trainees: two upper-body sessions and two lower-body sessions train the major muscle groups twice per week while leaving three rest days in a standard seven-day training week.

• A 4-day split can support muscle growth and strength gains when weekly training volume, loading, recovery, and progressive overload are appropriate. The split itself is not what builds muscle.

• Consistency matters: a four-day schedule works best with consistent training and when you can follow the training plan consistently. If four sessions are difficult to fit into most weeks, a three-day split is usually easier to manage.

• Compound lifts are usually prioritized early in the workout, while isolation exercises can add direct work for specific muscle groups. The most important exercise should come first, especially when strength in that movement is a priority.

What Does a 4-Day Workout Split Mean?

The term is used in two different ways, and it is worth separating them from the start because many online discussions about training splits simply mix the two meanings together.

In the strict sense, a training split describes how many sections the body's muscle groups are divided into. A four-way body part split then means a program in which the body is divided into four parts and each muscle group is trained once per week, for example: 1) chest and triceps, 2) back and biceps, 3) legs, and 4) shoulders and abs. A single muscle group often receives a large stimulus in one session, but then waits seven days for the next stimulus, leaving a fairly long recovery period.

In everyday use, however, the definition of a “4-day workout split” has broadened. Today, the term is often used for any program with four different workouts per week, even if the body is only divided into two sections. The most common example is an Upper/Lower Split with two different workout pairs: the program then has two upper-body sessions and two lower-body sessions, and each muscle group is trained twice per week.

For clarity, this article uses the term in its strict sense while presenting effective solutions for both definitions. In templates 1–3, four different workouts cycle the muscle groups twice per week. Template 4 is the traditional split in which the body is divided into four sections.

All of the examples share the same weekly structure: four workouts and three rest days per week. This is not necessarily very flexible. Travel, illness, and busy work periods can easily disrupt the rhythm because you need to fit four training opportunities into seven days. If your training weeks are irregular, a 3-day split workout program handles life's unpredictability better.

What Does Research Say About Workout Splits?

At this point, many people expect an answer to the question, “What is the best workout split?” The answer is somewhat nuanced.

Ramos-Campo and colleagues pooled 14 studies and almost 400 trainees in a meta-analysis comparing split routines with full-body programs. They found no difference in muscle growth or strength on any outcome measure (Ramos-Campo et al. 2024). In most of the studies, training volume, loads, and proximity to failure were matched between groups, meaning the main variable that differed was how often each muscle group was trained.

A more detailed picture comes from the meta-regression by Pelland and colleagues, which combined 67 studies and more than 2,000 trainees (Pelland et al. 2026). Weekly set volume predicted both muscle growth and strength, although with diminishing returns: each additional set produced less benefit than the previous one. When weekly volume was the same, training frequency did not have a meaningful effect on muscle growth. For strength development, however, a higher weekly frequency was more effective.

The split itself therefore does not build muscle. Its role is to determine how easily you can accumulate enough high-quality sets for each muscle group over the week and organize work for specific muscle groups. It is still common to recommend structuring training so that each muscle group is trained twice per week. The reason is practical: focused sessions make it easier to perform high-quality sets when weekly work is divided across workouts than when you try to complete all of a single muscle group's weekly sets in one session, where fatigue can reduce set quality toward the end.

When evaluating a program, it therefore makes more sense to look at weekly set volume by muscle group and how well it fits you. The name of the split says less about training effectiveness than many people assume.

Once or Twice per Week?

A common criticism of the traditional four-way split is that each muscle group is trained only once per week. The claim is only partly true, and it is worth unpacking carefully.

Schoenfeld and colleagues pooled frequency studies in a meta-analysis, and the result was clear: when weekly set volume was matched, training frequency had no significant effect on muscle growth (Schoenfeld et al. 2019). In the studies, people who trained more often tended to grow slightly more mainly when they also performed more total sets. Pelland's more recent analysis reached the same conclusion (Pelland et al. 2026). In these comparisons, weekly sets for a muscle group were typically distributed across one to three normal-sized training sessions, so the result does not mean that doing all of the week's training in one session would be equally effective. It does suggest, however, that total weekly set volume is a more relevant variable than the number of sessions itself.

So why is it still commonly recommended to distribute a muscle group's volume over multiple workouts?

There is a limit to how much useful volume you can perform in one session. Remmert and colleagues specifically modeled per-session volume and found that the benefit increased more slowly as the number of sets rose, with the additional return becoming uncertain after roughly ten sets (Remmert et al. 2025). This is still a manuscript awaiting peer review, so the exact number should not be overemphasized. The direction of the finding still matches practical experience: twenty chest sets on Monday do not produce twice the results of ten, but they do create substantially more fatigue.

Frequency is primarily a way to divide weekly training volume into sensible doses and allow proper rest between repeated sessions for the same area. If each muscle group is trained twice per week, 12–16 weekly sets can be split into two sessions of 6–8 sets, allowing each set to be performed relatively fresh. Packing the same amount into one workout means the later sets are performed with lighter weights and under greater fatigue. We cover training frequency in more detail in our guide on how often you should go to the gym.

How Many Sets per Muscle Group per Week?

There is no single correct number, but there is a useful range. In Pelland's data, muscle growth increased with set volume with diminishing returns, and no clear ceiling was found within the studied volume levels (Pelland et al. 2026). A review by Baz-Valle concluded that 12–20 sets per muscle group per week was a reasonable recommendation for young, resistance-trained men, although it was based on a fairly small body of studies (Baz-Valle et al. 2022).

In practice, 5–20 sets per muscle group per week is a useful adjustment range. A beginner can progress near the lower end because a smaller dose is enough to drive adaptation. A more experienced trainee typically needs around ten sets or more, and volume should only be increased when progress stalls and recovery remains adequate under the current workload. In the ready-made templates in this article, most muscle groups receive about 7–14 direct sets per week, leaving room to add work where you need it most.

A common scientific approach is to count volume as direct sets: a muscle group only receives credit for exercises in which it is the primary target. This method is unambiguous and keeps the numbers comparable from week to week, and the AITOFIT workout app calculates volume in the same way.

Direct volume is not the whole picture, however, because compound exercises and other compound movements also load assisting muscles. Bench presses train the triceps, rows train the biceps, and squats train the glutes. For example, bench pressing appears to grow the triceps at roughly half the rate of direct triceps work (Henselmans 2024). Six sets of dumbbell rows will still be felt in the biceps even if the program contains no direct biceps sets. In practice, indirect loading is accounted for by setting a lower direct-volume target for muscle groups that receive a lot of secondary work, such as the arms. That is why the examples below include only a few direct sets for the biceps and triceps: the table counts direct volume only.

The same issue appears differently in the lower body. Squats, leg presses, and lunges are lower body exercises that load the quadriceps and glutes, but they provide little work for the hamstrings (Kubo et al. 2019). The hamstrings need their own direct sets from a hip-hinge movement and leg curls, which is why every template in this article contains both movement patterns.

Four Effective 4-Day Split Templates

Below are four different ways to structure a four-day split. Templates 1 and 4 are written out in full, while templates 2 and 3 are shown at the structural level. Every template includes both compound lifts and isolation exercises.

Two general rules apply to all of them. Do the most important exercise first: strength improves most in exercises performed at the beginning of a workout, whereas exercise order has little effect on muscle growth (Nunes et al. 2021). The priority exercise is usually one of the main compound movements, but when addressing a weakness it can be something else. Rest periods should generally be 2–4 minutes for compound exercises and 1–3 minutes for isolation exercises because overly short rests reduce the number of reps you can perform in the next set and, in turn, reduce total weekly volume.

Template 1: Upper Body and Lower Body Twice per Week

This is the best starting point for most people. The program contains four different workouts: two upper-body sessions and two lower-body sessions with different emphases, giving room to develop both upper body strength and lower body strength. Each muscle group is trained twice per week, and every main lift is performed relatively fresh because three days have passed since the previous workout that heavily loaded the same area. For an intermediate trainee, this is a controlled way to increase volume when a 2-day split is no longer enough. The program is also flexible because, when necessary, upper- and lower-body exercises can be performed on back-to-back days without repeating the same primary muscle groups.

The rep ranges in the example programs are designed to support both overall strength development and muscle growth. The upper body combines upper body pushing movements such as the bench press and incline dumbbell press with pulling movements such as pull-ups and seated cable rows, while the lower body sessions combine squats, leg press variations, leg curls, and calf raises. Bicep curls and other isolation exercises add direct arm work.

Monday, Upper Body A (horizontal emphasis)

• Bench press 4×5–8

• One-arm dumbbell row 3×8–12

• Incline dumbbell press 3×8–12

• Lat pulldown 3×8–12

• Lateral raise 3×12–16

• Barbell curl 3×8–12

Tuesday, Lower Body A (quadriceps emphasis)

• Back squat 3×5–8

• Bulgarian split squat 3×8–12

• Lying leg curl 4×8–12

• Standing calf raises 4×8–15

• Cable crunch 3×10–15

Thursday, Upper Body B (vertical emphasis)

• Barbell overhead press 4×5–8

• Pull-ups 3×6–10

• Dip 4×8–12

• Seated cable row 3×10–15

• Face pull 3×12–20

• Cable triceps pushdown 3×8–12

Friday, Lower Body B (hamstring and glute emphasis)

• Romanian deadlift 3×6–10

• Leg press or hack squat 4×8–12

• Seated leg curl 3×8–12

• Seated calf raises 3×10–15

• Hanging leg raise 3×5–15

Here is how weekly volume is distributed by muscle group:

Muscle group	Volume (sets per week)
Chest	11
Back	12
Shoulders	10
Biceps	3
Triceps	3
Quadriceps	10
Hamstrings	10
Glutes	12
Calves	7

The numbers show the key point: the major muscle groups are all covered, and if one area is a priority, you can see where to add more work. Each workout takes roughly 60–75 minutes including rest periods. For a deeper look at exercise selection, see our guides to back workouts and shoulder workouts.

Template 2: Push, Pull, Legs, and Full Body

A three-day structure made up of push, pull, and leg days—commonly known as PPL—trains each muscle group only once per week. A fourth day fixes that problem.

• Monday: upper body push (chest, shoulders, triceps)

• Tuesday: pull (back, rear delts, biceps; pulling exercises)

• Thursday: legs

• Friday: full body

The Friday workout is built around your own weak points. If the hamstrings and upper back are lagging, Friday could include Romanian deadlifts 3×6–10, pull-ups 3×6–10, leg extensions 3×8–12, face pulls 3×12–20, and 2–3 sets of chest press.

Template 3: Lower-Body-Focused 4-Day Split

If lower body strength or muscle growth is your main priority—or the lower body clearly lags behind the upper body—you can tilt the split in that direction.

• Monday: lower body, quadriceps emphasis (back squat 4 sets, lunge 3 sets, leg extension 3 sets, calves 4 sets)

• Tuesday: Upper Body A (5–6 exercises based on horizontal presses and pulls, 3 sets each)

• Thursday: lower body, hamstring and glute emphasis (Romanian deadlift 4 sets, hip thrust 3 sets, leg curl 3 sets, calves 4 sets)

• Friday: Upper Body B (5–6 exercises based on vertical movements and arm work, 3 sets each)

This gives the lower body close to 20 working sets per week excluding calves: around ten for the quadriceps and a similar amount for the posterior chain. Upper-body muscle groups remain at roughly 8–12 weekly sets, which is enough for maintenance and moderate progress. You can find more exercise options in our leg workout and glute workout guides.

Template 4: Classic Body-Part Split, or Bro Split

This is a four-way split in the traditional sense: the body is divided into four sections and each muscle group is trained thoroughly once per week. The English nickname “bro split” has also become widely used in other languages.

Monday, chest and triceps

• Bench press 4×5–8

• Incline dumbbell press 3×8–12

• Cable crossover 3×10–15

• Barbell skull crusher 3×8–12

• Cable triceps pushdown 3×10–15

Tuesday, back and biceps

• Pull-up or lat pulldown 4×6–10

• Barbell bent-over row 3×8–12

• One-arm seated cable row 3×10–12

• Barbell curl 3×8–12

• Incline dumbbell curl 2×10–15

Thursday, legs

• Back squat 4×5–8

• Leg press 3×8–12

• Romanian deadlift 3×6–8

• Seated leg curl 3×10–15

• Standing calf raises 4×8–15

Friday, shoulders and abs

• Barbell overhead press 4×5–8

• Lateral raise 4×12–20

• Face pull 3×12–20

• Cable crunch 3×10–15

• Ab wheel rollout 3×8–15

Does this work? Yes, as long as weekly volume is appropriate and you follow the program consistently. Based on the Ramos-Campo meta-analysis, a split routine does not underperform a full-body routine when sets and loads are matched (Ramos-Campo et al. 2024). For an experienced trainee who enjoys focused sessions, muscle isolation, and longer body-part workouts, this is a perfectly valid choice for at least part of the year.

There are still two things to keep in mind. The ten weekly chest sets and thirteen weekly back sets are performed in a single session, so the quality of the later sets inevitably drops. And because there is only one leg day, it has to cover several demanding lower-body exercises, which can make the workout feel very taxing.

For beginners, this is the weakest of the four templates. The exercise selection is broad, each movement is practiced relatively infrequently, and technique would develop faster with more frequent repetition. Beginners also do not need a large amount of volume in one session, so part of the work in this split would simply be unnecessary.

In short, the best split is always individual. It is worth choosing coaching that takes responsibility for selecting a suitable split and can explain the reasoning behind it based on evidence.

How Should You Structure the Training Week?

The most common schedule is Monday, Tuesday, Thursday, and Friday: train Monday and Tuesday, rest Wednesday, then train Thursday and Friday before the weekend. This gives you four training days and three rest days in the week, and leaves three days between workouts that heavily load the same area.

Another effective schedule is Monday, Wednesday, Friday, and Saturday. Alternatively, you can ignore the seven-day week entirely and use a cycle of two training days followed by one rest day, in which case the same workout repeats every six days.

A few ordering rules make recovery easier. Do not place demanding exercises back to back when they heavily load the same structures: a heavy squat day and a heavy deadlift day should not be placed on consecutive days. If you do Romanian deadlifts on Thursday, do not schedule heavy squats for Friday. And if upper-body training repeatedly feels unusually hard, look at what you did the day before: a heavy deadlift session can tax the upper back and grip more than many people realize.

Progressive Overload Determines the Outcome

Without progressive overload, even the best program template stops working after a while. Record your sets and reps from every workout, because without numbers you cannot tell whether you are progressing or simply staying in place.

One of the simplest and most effective progression models works like this: keep the same weight and perform as many reps as the programmed rep range allows, adding reps over time until you reach the top of the range in every set. Then increase the weight and start again near the lower end of the range. For example, take a bench press prescription of 4×5–8. In week one, you might get 8, 7, 6, and 6 reps with 80 kg. Continue with the same weight until you can do 8 reps in all four sets. Then increase the weight to 82.5 kg and the reps will drop back to around five or six. The same logic works for every exercise. Over the long term, however, keeping gains steady requires a structured progression plan, such as varying rep ranges and exercises according to your development.

Reps in reserve—the number of repetitions you could still perform when a set ends—should generally remain between one and three for most sets. Isolation exercises can be taken closer to failure because recovery is faster and the technical risk is lower. In heavy compound exercises, leave 2–3 reps in reserve, because constantly training to failure accumulates fatigue faster than it produces additional benefit.

Increase volume gradually: adding 1–2 sets per muscle group every few weeks is enough, and only when there is a reason to believe the extra work will support further progress. The same principle applies to deload weeks. The higher your weekly volume, the more useful they become. There is little strong evidence for fixed timing, so “every eighth week” is more of a convention than a scientific rule. A better signal is performance: if the loads in several main lifts have not increased for two or three weeks, your joints are aching, and motivation to train is dropping, reduce set volume by roughly half for one week while keeping the weights close to normal. Keep the exercise selection the same.

This also highlights the basic problem with static programs. A four-day program downloaded from the internet is someone else's average guess. It knows nothing about how many reps you completed last week or whether you missed Thursday's workout. AITOFIT builds the split and exercise selection around your training history, recovery, and goals, and adjusts set volume and loads as you progress. We explain the logic in more detail in our article on how AI creates a workout program. The program evolves with you instead of becoming more outdated week by week.

Recovery Determines How Much Volume You Can Handle

Four training days allow more weekly sets than two, which is exactly why fatigue can also accumulate faster. Volume recommendations in research are measured in people who sleep enough and eat enough. If neither is true, 16 weekly sets per muscle group may be too much even if the number looks neat on paper.

It starts with sleep: seven to nine hours per night helps maintain force production and training quality, and technique is most likely to break down in the final sets when you are tired. For nutrition that supports muscle repair and recovery, two numbers cover the essentials: at least around 1.6 grams of protein per kilogram of body weight per day, with the meta-analysis confidence interval extending to roughly 2.2 grams, which is where the practical range of 1.6–2.2 g/kg comes from (Morton et al. 2018). Energy intake should be at least around maintenance level and slightly above it during a muscle-gain phase. We cover the topic in more detail in our guide to how much protein you need per day.

Endurance training can fit alongside strength training well when it is scheduled sensibly. A couple of easy 30–45-minute sessions per week will not interfere with muscle growth. High-intensity intervals should be kept away from squat and deadlift days so the legs have time to recover for both types of training.

Five Ways to Ruin a 4-Day Split

Legs are left to one day—or left out entirely. Hulmi (2019) highlights this as one of the most common problems with multi-day split training in the gym: the upper body is trained two to four times per week and the legs once, if at all. The lower body accounts for roughly half of the body's muscle mass.

Too many small isolation exercises. Four workouts per week create room to add exercises, and soon the program contains three different lateral-raise variations and two forearm exercises but only three squat sets. The time commitment becomes disproportionate to the benefit.

Doing a four-day split only three times per week. The rotation then stretches to more than nine days, each muscle group is trained less often than once per week, and tracking weekly volume becomes awkward. With three training sessions per week, a two- or three-way split fits the week more cleanly.

Using the same program year after year. Progressive overload eventually stalls, and the program stops producing progress. At that point, something needs to change: exercises, set volume, frequency, or the split itself.

Technique deserves particular attention because with four weekly workouts, errors are repeated more often than with two. Keep proper form and controlled movement as you progress the load. Review deadlift technique and bench press technique before increasing the weights substantially, and make sure your breathing technique is sound during heavy sets.

Who Is a 4-Day Split For—and Who Is It Not For?

A 4-day program can be a good fit if you can keep training consistently four times per week, have been strength training regularly for at least six months, want to build muscle and emphasize specific weak points, and enjoy workouts that last roughly an hour.

Skip a four-day split if your training weeks are irregular, you are just starting at the gym, or you need a program that can tolerate the occasional missed workout.

For beginners, a two- or three-way split usually produces a better result, although the same can also be true for many experienced trainees depending on the individual. The basic lifts are repeated more often, technique develops faster, and the whole body still receives a training stimulus even if you only train twice in a given week. For your first six months, a beginner gym workout program is usually a better fit, followed by a 3-day split workout program as an intermediate step.

Summary

A 4-day workout split is a good choice when four gym sessions per week happen consistently. There is no single best workout split for everyone: weekly set volume, sufficient loading, recovery, and progressive overload are the variables that support muscle growth and strength development (Ramos-Campo et al. 2024; Pelland et al. 2026).

For most people, the most practical four-day split distributes each muscle group's work across two days per week. This is not a biological requirement, but in practice it keeps individual workouts reasonably short and helps maintain set quality. An Upper/Lower Split performed twice per week does this almost automatically, which is why it is the most practical default presented here for many people. A traditional body-part split can also work as long as weekly volume is appropriate and leg day stays in the program.

If you do not want to guess how many sets to perform, which exercises to choose, or when the program should change, AITOFIT does it for you. The app was developed by exercise science professionals from the University of Jyväskylä, has received more than 5,400 reviews with an average rating of 4.9/5, and costs €14.90/month. Try AITOFIT free for 9 days without a credit card.

Frequently Asked Questions

Is a 4-day split better than a 3-day split?

Not automatically. Based on meta-analyses, the structure of the split does not determine muscle growth when weekly volume and loads are the same (Ramos-Campo et al. 2024; Pelland et al. 2026). The advantage of a 4-day split is that it gives you more room for isolation exercises and emphasizing weak points. A 3-day split, on the other hand, handles irregular weeks better.

Can you do a four-day split three times per week?

You can, but it is rarely ideal. With only three sessions per week, a four-workout rotation stretches beyond nine days, meaning each muscle group is trained less often than once per week and weekly volume becomes harder to track. A two- or three-way split designed around three weekly sessions is simpler.

How many exercises should one workout include?

As a rule of thumb, five to seven working exercises and roughly 15–25 working sets per session is enough for almost everyone. A workout routine can combine free weights, machines, compound exercises, and isolation exercises; if you need ten exercises in one session, the exercise selection is probably not optimal.

How long should a 4-day split workout take?

About 45–75 minutes including warm-ups. Rest periods for compound exercises should generally be kept around 2–3 minutes because overly short rests reduce rep performance and therefore total volume.

Is a 4-day split suitable for beginners?

Usually not in the best possible way. Beginners benefit from repeating the basic lifts frequently and training the whole body more often. A two- or three-way split generally serves the first six months better.

How often should you change your workout split?

Change it when progressive overload stalls or motivation starts to fade. If progress is still moving and the plan fits your schedule, stay consistent rather than changing the split just for variety. If the program itself is well designed, adapts as you progress, and works for you, there may be no need to change the split for years.

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Sources: Baz-Valle, E., Balsalobre-Fernández, C., Alix-Fages, C. & Santos-Concejero, J. (2022). A Systematic Review of the Effects of Different Resistance Training Volumes on Muscle Hypertrophy. Journal of Human Kinetics. Henselmans, M. (2024). How to count training volume and design a sensible training split. mennohenselmans.com. Hulmi, J. (2019). Monijakoinen harjoittelu – uhka vai mahdollisuus? Lihastohtori. Kubo, K., Ikebukuro, T. & Yata, H. (2019). Effects of squat training with different depths on lower limb muscle volumes. European Journal of Applied Physiology. Morton, R. W., Murphy, K. T., McKellar, S. R. et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. Nunes, J. P., Grgic, J., Cunha, P. M., Ribeiro, A. S., Schoenfeld, B. J., de Salles, B. F. & Cyrino, E. S. (2021). What influence does resistance exercise order have on muscular strength gains and muscle hypertrophy? A systematic review and meta-analysis. European Journal of Sport Science. Pelland, J. C. et al. (2026). The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains. Sports Medicine 56(2), 481–505. Ramos-Campo, D. J., Benito-Peinado, P. J., Andreu-Caravaca, L., Rojo-Tirado, M. A. & Rubio-Arias, J. Á. (2024). Efficacy of Split Versus Full-Body Resistance Training on Strength and Muscle Growth: A Systematic Review With Meta-Analysis. Journal of Strength and Conditioning Research. Remmert, J. F. et al. (2025). Is There Too Much of a Good Thing? Meta-Regressions of the Effect of Per-Session Volume on Hypertrophy and Strength. SportRxiv (manuscript not yet peer reviewed). Schoenfeld, B. J., Grgic, J. & Krieger, J. (2019). How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. Journal of Sports Sciences. Tikka, M. (2012). Treenijako for dummies. Lihastohtori. Zourdos, M. C. (2024). When to Use Split- and Full-Body Training Programs. MASS Research Review, Vol 8, Issue 6. Zourdos, M. C. (2022). When and How to Increase Training Frequency. MASS Research Review, Vol 6, Issue 12.

Author: Tapio Tulenheimo, M.Sc Exercise Science (Exercise Physiology), University of Jyväskylä | Reviewed by: Julius Granlund, M.Sc Exercise Science (Exercise Physiology), University of Jyväskylä