Exercise Parameters in Physical Therapy

These parameters influence physiological, neuromuscular, and psychological adaptations and are central to creating individualized, evidence-based rehabilitation programs.

Is manipulating parameters necessary?

Adjustment of training variables allows you to:

• Stimulate progressive overload and strength gains, making your patients stronger and more physically capable,
• Facilitate tissue adaptation (e.g., tendon remodeling),
• Alleviate pain and improve functional movement,
• Control exercise intensity and track progress,
• Adapt programs based on condition-specific needs (e.g., tendinopathy).

Exercise parameters you need to know

Type of muscle action

• Concentric: Muscle shortens,
• Eccentric: Muscle lengthens,
• Isometric: Muscle contracts without movement (holding),
• Dynamic: Combines concentric and eccentric actions.

Load/Resistance

• Defined by weight (kg) or % of 1-RM (Repetition maximum),
• Heavy loads (>60% 1-RM) build strength, while moderate to light loads to failure can enhance hypertrophy (building muscle).

Load is a primary driver of both muscle and tendon adaptation!

Sets and Repetitions

Those two are fundamental to calculating training volume. More reps generally favor hypertrophy; fewer reps at high loads favor strength, but remember that those parameters need to be individualized! Don’t throw your patient into a vicious cycle of 3x8 or 3x12 just because you’ve seen it somewhere in social media. Tailor the amount of sets and repetitions to an individual for best results possible.

Range of Motion (ROM)

Full ROM activates more muscle and may produce superior strength and hypertrophy outcomes while partial ROM might be warranted during early rehab or for isolation.

Time under tension (TUT) and execution velocity

Slower tempo increase TUT, influencing metabolic and mechanical stress. However, if you want to boost power and hypertrophy, you may use faster velocities in your patients’ training.

Rest Intervals

Usually, longer rest periods (1–2+ minutes) support force production and recovery, and are utilized during power training or isometric session. Meanwhile, short rests might enhance metabolic stress, useful in certain hypertrophy programs or tabata workouts where the aim is to build more cardiac capabilities.

An important factor during exercise session, that is often overlooked is an attentional focus. By attentional focus we understand internal and external focus when performing an exercise:

• Internal focus (thinking about the muscle) can improve muscle activation,
• External focus (thinking about the task) can enhance movement efficiency and strength output.

Rating of Perceived Exertion (RPE)

What is RPE?

RPE is the perception of effort, fatigue, and exertion experienced during physical activity. It reflects a psychosomatic interaction—the brain’s interpretation of physiological strain (muscle fatigue, breathlessness, chest tightness, etc.).

Why Use RPE in Physical Therapy?

• A low-cost, accessible way to monitor and regulate intensity
• Helps prevent overtraining or under-stimulation
• Enhances communication and supports exercise adherence
• Especially useful in older adults and clinical populations

Physiological Relevance of RPE

RPE is strongly correlated with:

• Heart rate
• Lactate levels
• Cortisol concentrations

For example, eccentric actions may feel less difficult than concentric actions at the same workload—but can generate higher forces and stress the tissue more. Over time, you may notice that the same training causes lower RPE than normal, which may mean that training or some exercises should be progressed. The opposite situation may also occur - suddenly the same training can become a big challenge for the patient. This may indicate that regression will be necessary or there are other factors that affect the RPE value (stress in everyday life, insomnia, chronic disease, etc.). Therefore, it is worth using such a simple scale in your practice to observe your patient and try to match the loads to their current condition.

Effective physical therapy programming requires  personalization, and feedback tools. By manipulating exercise parameters—including type of contraction, load, rest, volume, duration and attentional cues—and using tools like RPE you can ensure exercises are appropriately intense, effective, and patient-centered.

Understanding and implementing these concepts supports progressive loading, pain reduction, and functional recovery, while respecting patient tolerance and promoting long-term adherence!

References:

Coratella, G. Appropriate Reporting of Exercise Variables in Resistance Training Protocols: Much more than Load and Number of Repetitions. Sports Med - Open8, 99 (2022). https://doi.org/10.1186/s40798-022-00492-1

Ferreira SS, Krinski K, Alves RC, Benites ML, Redkva PE, Elsangedy HM, Buzzachera CF, Souza-Junior TP, da Silva SG. The Use of Session RPE to Monitor the Intensity of Weight Training in Older Women: Acute Responses to Eccentric, Concentric, and Dynamic Exercises. J Aging Res. 2014;2014:749317. doi: 10.1155/2014/749317. Epub 2014 Apr 13. PMID: 24834354; PMCID: PMC4009156.

Hollander DB, Durand RJ, Trynicki JL, Larock D, Castracane VD, Hebert EP, Kraemer RR. RPE, pain, and physiological adjustment to concentric and eccentric contractions. Med Sci Sports Exerc. 2003 Jun;35(6):1017-25. doi: 10.1249/01.MSS.0000069749.13258.4E. PMID: 12783051.

Lum D, Comfort P, M. Barbosa T, Balasekaran G. Comparing the effects of plyometric and isometric strength training on dynamic and isometric force-time characteristics. Biology of Sport. 2022;39(1):189-197. doi:10.5114/biolsport.2022.103575.

Prudêncio, D.A., Maffulli, N., Migliorini, F. et al. Eccentric exercise is more effective than other exercises in the treatment of mid-portion Achilles tendinopathy: systematic review and meta-analysis. BMC Sports Sci Med Rehabil15, 9 (2023). https://doi.org/10.1186/s13102-023-00618-2

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