You're training – but somehow it's missing the kick? No wonder, because a few squats and a bit of bench pressing aren't enough to really challenge your body.
What you need are four training stimuli: Intensity, volume, frequency and tension.
Whether you want to get stronger, build muscle or just be fitter, these building blocks are the foundation for making progress.
In this article, you'll learn how to incorporate these stimuli into your training in a clever way so you can finally get more out of yourself and each session.
What are the 4 training stimuli and why are they crucial?
The four training stimuli – intensity, volume, frequency and tension – are the foundation of every effective workout. They determine whether you build muscle, increase strength or improve your endurance.
Each stimulus has a specific function:
Intensity: How hard do you train? The intensity controls how much your muscles and nervous system are challenged.
Volume: How much work are you doing? Volume is crucial for muscle growth and endurance.
Frequency: How often do you train? Regular stimuli promote progress and technique.
Tension: How effectively are you straining your muscles? Targeted tension ensures maximum activation.
Combined correctly, these stimuli will take your training to the next level – whether you're a beginner or a pro.
Training stimulus intensity – why is it so important?
Intensity describes how hard you train. In strength training, it is usually expressed as a percentage of your 1RM (one-rep max) – the maximum weight you can lift for a single repetition. The higher the weight, the greater the intensity.
Why intensity is the engine of progress
Intensity determines how strong your muscle growth stimulus is and what kind of adaptation your body makes.
High intensity (80-90% of your 1RM): Perfect for building strength. Your nervous system is challenged to the max and your muscles adapt to handle heavier loads.
Moderate intensity (60-75%): Optimal for muscle growth (hypertrophy). These weight ranges allow you to do more reps, which creates more volume.
Low intensity (40-60%): Good for endurance training or rehabilitation. You work with more repetitions and less load.
How do I increase the intensity properly?
Progressive overload: Increase either the weight or the number of repetitions every 2-3 weeks. Example: If you can bench press 60 kg for 8 reps, try 62.5 kg next time.
Periodization: Alternating between intensive phases (high weights, few repetitions) and moderate phases (more repetitions, lighter weights).
Common mistakes in intensity
Exercising too lightly: Beginners in particular underestimate what they can lift and thus miss out on important stimuli.
Too difficult to practise: Without proper technique, you risk injury – a no-go.
Training stimulus volume: More repetitions, more progress?
Volume is the total amount of work you do during a workout. It is calculated as:
Sets x reps x weight
Why volume is what makes muscles grow
Volume is particularly important for muscle growth. The more work your muscle does, the greater the growth stimulus.
But be careful: too much volume can overwhelm you and negatively affect your recovery.
Beginners: 10-12 sets per muscle group per week is ideal.
Advanced: 15-20 sets per week, spread over several sessions.
Professionals: 20+ sets per week, if recovery is good.
How do I determine the optimal volume?
Split up instead of overloading: Instead of doing 15 sets of chest presses in one day, split them up into two sessions. This helps you maintain a high level of quality.
Use variety: Combine basic exercises (e.g. bench presses) with isolation exercises (e.g. bicep curls) to challenge different aspects of your muscles.
Common volume mistakes
“More is better” mindset: If you do too many sets, you risk overtraining. Your body needs time to recover.
Insufficient volume: Especially when building muscle, the effects will be lost if you don't do enough reps or sets.
Training stimulus frequency: How often should I train?
A muscle that is trained more often will receive more growth stimuli. But that doesn't mean you should train the same muscle every day – recovery is just as important.
The right frequency ensures that your training is more efficient and that you can better distribute your volume (i.e. your total workload).
The advantages of a higher frequency:
More frequent stimulation: Muscles adapt faster when they are challenged regularly.
Better recovery: Instead of doing 15 sets of a muscle group in one day, you can do 7-8 sets spread over two sessions. This keeps the quality high and reduces fatigue.
Improved technique: Repeated training improves the execution of complex movements such as squats or pull-ups.
How often should I train?
The optimal frequency depends on your goal and your training level – and on how quickly you recover.
Beginners: 2-3 times per week
Example: Full body workout. Every unit covers all the major muscle groups.
Advantage: Even load, rapid progress through frequent stimulation.
Advanced: 4-5 times per week
Example: Split plan (e.g. upper body/lower body or push/pull).
Advantage: Higher volume, better focus on individual muscle groups.
Professionals: Up to 6 times per week
Example: Push/pull/leg splits with moderate volume per unit.
Advantage: Maximum growth stimulus with sufficient recovery.
Common mistakes in training frequency
Not training often enough: Once a week per muscle is often not enough to make progress, especially when building muscle.
Training too often: If you train the same muscle every day, you risk overtraining and stagnating faster.
No variation: Always using the same frequency and exercise selection can lead to plateaus.
Training stimulus: The underestimated key to tension
To be honest, without mechanical tension, not much happens. Your muscle only grows when it is taken out of its comfort zone.
And that happens when it is controlled and intensely strained. It's not the weight alone that makes the difference, but how you move it.
Maximum activation of muscle fibers: Slow and controlled movements ensure that more muscle fibers are activated.
Muscle growth: More time under tension (TUT) increases the growth stimulus.
Joint-friendly training: By focusing on proper form, you can create high tension without putting undue stress on the joints.
How can I create suspense in a targeted way?
Slow eccentric movements: The eccentric part (e.g. lowering the dumbbell) should be slow and controlled. Count to three or four as you lower the weight.
Hold: Pause at the most difficult part of the movement, such as just above the chest when bench pressing. Hold for one to two seconds to maximize tension.
Full range of motion: Work through your entire range of motion – from fully extended to fully contracted.
Common mistakes when tensioning
Fast, uncontrolled movements: If you rush through exercises, you lose the tension and thus the growth stimulus.
Excessive weight: If you rely on momentum instead of activating the muscle in a targeted way, the effect is lost.
No concentration on the target muscle: Make sure that you feel which muscle is working during the movement.
How do I combine all 4 training stimuli optimally?
The combination of intensity, volume, frequency and tension is the key to an effective workout.
Each stimulus has a specific role and should be adjusted based on your goal – muscle building, strength training or endurance. But how exactly do you use all four stimuli sensibly?
1. Set your goal
Before combining all the stimuli, you need to know what goal you are pursuing. Each goal requires a different weighting of the stimuli:
Muscle building: The focus is on volume and tension. You work with moderate weights (60-75% of your 1RM), do 8-12 repetitions and use a slow, controlled execution.
Strength building: Here, the focus is on intensity. You train with heavy weights (80-90% of your 1RM), reduce the repetitions to 3-5 and take longer breaks between sets.
Endurance and fat burning: Volume and frequency are the main focus here. You use lighter weights, higher numbers of repetitions (12-20) and shorter breaks to keep your heart rate high.
2. Plan your training week sensibly
To integrate all four stimuli, you can divide the week into different focal points.
A 3-day plan could look something like this:
Day 1: Focus on intensity
Goal: Strength building.
Exercises: Squats, bench presses, deadlifts (4-5 sets of 3-5 reps each).
High intensity (80-90% of 1RM), longer rests (2-3 minutes).
Day 2: Focus on volume
Goal: Muscle building.
Exercises: Incline bench presses, rowing, lunges (3-4 sets of 8-12 reps each).
Moderate weight (60-75% of 1RM), shorter rests (60-90 seconds).
Day 3: Focus on voltage
Goal: Maximum muscle activation.
Exercises: Romanian deadlift, plank, Bulgarian split squats (3 sets, slow, eccentric phase with 3-4 seconds).
Full range of motion and conscious contractions.
3. Apply progressive overload
No matter how you combine the stimuli, progression is the key. Your body adapts to stress, so you have to challenge it again and again. Here are some strategies:
Increase weight: Increase weight by 2.5-5% every 2-3 weeks.
Increase volume: Add another set or a few more repetitions.
Shorten breaks: Reduce breaks between sets to increase intensity.
Slow down movement: Maintain tension by moving more slowly.
4. Avoid common mistakes
Too much focus on one stimulus: If you only focus on intensity, you lack volume and tension – and vice versa.
No recovery: Too much volume and frequency without recovery leads to overtraining. Plan for at least one rest day per week.
Lack of technique: Especially when it comes to tension and intensity, clean execution is important.
Training stimuli: A plan for more success
As you can see, the four stimuli – intensity, volume, frequency and tension – are like interlocking gears. You will only achieve maximum results if you use them all in a targeted manner.
Whether you want to get stronger or build muscle, now you know the tools to take your training to the next level.
