Jorn Trommelen, PhD
@jorntrommelen.bsky.social
Assistant professor. Muscle Metabolism.
November 21, 2025 at 2:10 PM
10/10 - Thank you to all the collaborators & participants who made this project possible. Follow @jorntrommelen for more evidence-based threads on exercise, nutrition & metabolism. Please like & share the first tweet linked below to help spread the word:
bsky.app/profile/jorn...
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Does interval training boost muscle protein synthesis more than continuous exercise?
HIIT vs MICT
✅ Within-participant design
✅ Unilateral cycling model
✅ MPS over 2 weeks
Let’s break it down (1/10)
HIIT vs MICT
✅ Within-participant design
✅ Unilateral cycling model
✅ MPS over 2 weeks
Let’s break it down (1/10)
November 21, 2025 at 2:08 PM
10/10 - Thank you to all the collaborators & participants who made this project possible. Follow @jorntrommelen for more evidence-based threads on exercise, nutrition & metabolism. Please like & share the first tweet linked below to help spread the word:
bsky.app/profile/jorn...
bsky.app/profile/jorn...
In conclusion, high-intensity interval training does not enhance myofibrillar protein synthesis rates when compared to volume- and duration-matched moderate intensity continuous exercise.
Open-access link:
journals.humankinetics.com/view/journal...
9/10
Open-access link:
journals.humankinetics.com/view/journal...
9/10
November 21, 2025 at 2:08 PM
In conclusion, high-intensity interval training does not enhance myofibrillar protein synthesis rates when compared to volume- and duration-matched moderate intensity continuous exercise.
Open-access link:
journals.humankinetics.com/view/journal...
9/10
Open-access link:
journals.humankinetics.com/view/journal...
9/10
Limitations were that single-leg cycling does not reflect real-world training and that habitual physical activity was not controlled.
8/10
8/10
November 21, 2025 at 2:08 PM
Limitations were that single-leg cycling does not reflect real-world training and that habitual physical activity was not controlled.
8/10
8/10
A major strength was the one-leg within-subject design with volume- and duration-matched protocols, which allowed a clean comparison of exercise intensity.
7/10
7/10
November 21, 2025 at 2:08 PM
A major strength was the one-leg within-subject design with volume- and duration-matched protocols, which allowed a clean comparison of exercise intensity.
7/10
7/10
These findings suggest that even higher-intensity endurance exercise is not a strong stimulus for muscle protein synthesis.
This aligns with long-term studies showing minimal impact of endurance exercise intensity on gains in fat-free mass.
6/10
This aligns with long-term studies showing minimal impact of endurance exercise intensity on gains in fat-free mass.
6/10
November 21, 2025 at 2:08 PM
These findings suggest that even higher-intensity endurance exercise is not a strong stimulus for muscle protein synthesis.
This aligns with long-term studies showing minimal impact of endurance exercise intensity on gains in fat-free mass.
6/10
This aligns with long-term studies showing minimal impact of endurance exercise intensity on gains in fat-free mass.
6/10
Key findings:
• Single-leg maximal workload and VO2peak improved with both HIIT and MICT.
• Myofibrillar protein synthesis did not differ between HIIT, MICT, or the control period.
5/10
• Single-leg maximal workload and VO2peak improved with both HIIT and MICT.
• Myofibrillar protein synthesis did not differ between HIIT, MICT, or the control period.
5/10
November 21, 2025 at 2:08 PM
Key findings:
• Single-leg maximal workload and VO2peak improved with both HIIT and MICT.
• Myofibrillar protein synthesis did not differ between HIIT, MICT, or the control period.
5/10
• Single-leg maximal workload and VO2peak improved with both HIIT and MICT.
• Myofibrillar protein synthesis did not differ between HIIT, MICT, or the control period.
5/10
Each of the ten subjects trained one leg with HIIT and the other with MICT, with both protocols matched for total volume and duration.
4/10
4/10
November 21, 2025 at 2:08 PM
Each of the ten subjects trained one leg with HIIT and the other with MICT, with both protocols matched for total volume and duration.
4/10
4/10
We compared High-Intensity Interval Training (HIIT) and Moderate Intensity Continuous Training (MICT) over two weeks.
Myofibrillar protein synthesis rates were assessed, reflecting the synthesis of muscle contractile proteins.
3/10
Myofibrillar protein synthesis rates were assessed, reflecting the synthesis of muscle contractile proteins.
3/10
November 21, 2025 at 2:08 PM
We compared High-Intensity Interval Training (HIIT) and Moderate Intensity Continuous Training (MICT) over two weeks.
Myofibrillar protein synthesis rates were assessed, reflecting the synthesis of muscle contractile proteins.
3/10
Myofibrillar protein synthesis rates were assessed, reflecting the synthesis of muscle contractile proteins.
3/10
Endurance training improves oxygen uptake and mitochondrial function.
Interval training is often promoted as a time-efficient alternative to steady continuous cardio, and some claim it might even stimulate more muscle growth.
2/10
Interval training is often promoted as a time-efficient alternative to steady continuous cardio, and some claim it might even stimulate more muscle growth.
2/10
November 21, 2025 at 2:08 PM
Endurance training improves oxygen uptake and mitochondrial function.
Interval training is often promoted as a time-efficient alternative to steady continuous cardio, and some claim it might even stimulate more muscle growth.
2/10
Interval training is often promoted as a time-efficient alternative to steady continuous cardio, and some claim it might even stimulate more muscle growth.
2/10
Follow me @jorntrommelen for more evidence-based threads on exercise & nutrition.
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
Motivation is not enough, make a concrete plan!
Exercise participation and:
- Impact of education?
- Impact of concrete planning?
Let’s break it down!
1/x
Exercise participation and:
- Impact of education?
- Impact of concrete planning?
Let’s break it down!
1/x
November 13, 2025 at 3:40 PM
Follow me @jorntrommelen for more evidence-based threads on exercise & nutrition.
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
In conclusion, education about the health benefits of exercise alone increases motivation but may not increase exercise participation. Adding a concrete plan specifying what, when, and where to exercise substantially increases participation.
Study:
www.ncbi.nlm.nih.gov/pubmed/14596...
10/10
Study:
www.ncbi.nlm.nih.gov/pubmed/14596...
10/10
Combining motivational and volitional interventions to promote exercise participation: protection motivation theory and implementation intentions - PubMed
It is concluded that supplementing PMT with implementation intentions strengthens the ability of the model to explain behaviour. This has implications for health education programmes, which should aim to increase both participants' motivation and their volition.
www.ncbi.nlm.nih.gov
November 13, 2025 at 3:40 PM
In conclusion, education about the health benefits of exercise alone increases motivation but may not increase exercise participation. Adding a concrete plan specifying what, when, and where to exercise substantially increases participation.
Study:
www.ncbi.nlm.nih.gov/pubmed/14596...
10/10
Study:
www.ncbi.nlm.nih.gov/pubmed/14596...
10/10
A strength of the study was the large sample size. Limitations include the very short study duration (1 week) and the outcome was based on self-reported session (not objectively verified).
9/x
9/x
November 13, 2025 at 3:40 PM
A strength of the study was the large sample size. Limitations include the very short study duration (1 week) and the outcome was based on self-reported session (not objectively verified).
9/x
9/x
Creating a specific plan such as deciding what, when and where to exercise, can help turn intentions into action. This strategy, known as implementation intentions, has been shown to work for other behaviors as well.
8/x
8/x
November 13, 2025 at 3:39 PM
Creating a specific plan such as deciding what, when and where to exercise, can help turn intentions into action. This strategy, known as implementation intentions, has been shown to work for other behaviors as well.
8/x
8/x
Interpretation:
This study shows that information alone can increase motivation, but that this does not always lead to behavior change. Even motivated individuals may fail to act.
7/x
This study shows that information alone can increase motivation, but that this does not always lead to behavior change. Even motivated individuals may fail to act.
7/x
November 13, 2025 at 3:39 PM
Interpretation:
This study shows that information alone can increase motivation, but that this does not always lead to behavior change. Even motivated individuals may fail to act.
7/x
This study shows that information alone can increase motivation, but that this does not always lead to behavior change. Even motivated individuals may fail to act.
7/x
Key finding (2/2):
- Education combined with a planning task increased both motivation and actual exercise participation (91% of participants exercised at least once in the week following the intervention).
6/x
- Education combined with a planning task increased both motivation and actual exercise participation (91% of participants exercised at least once in the week following the intervention).
6/x
November 13, 2025 at 3:39 PM
Key finding (2/2):
- Education combined with a planning task increased both motivation and actual exercise participation (91% of participants exercised at least once in the week following the intervention).
6/x
- Education combined with a planning task increased both motivation and actual exercise participation (91% of participants exercised at least once in the week following the intervention).
6/x
Key finding (1/2):
- Education alone increased the motivation to exercise but did not increase actual exercise participation; many participants reported being ‘too busy to exercise’.
5/x
- Education alone increased the motivation to exercise but did not increase actual exercise participation; many participants reported being ‘too busy to exercise’.
5/x
November 13, 2025 at 3:39 PM
Key finding (1/2):
- Education alone increased the motivation to exercise but did not increase actual exercise participation; many participants reported being ‘too busy to exercise’.
5/x
- Education alone increased the motivation to exercise but did not increase actual exercise participation; many participants reported being ‘too busy to exercise’.
5/x
Groups:
1. Control: reading a neutral text (first three paragraphs of a novel)
2. Motivation: reading a leaflet with information about the health benefits of exercise
3. Planning: received the same leaflet plus completed a planning task specifying what, when, and where to exercise
4/x
1. Control: reading a neutral text (first three paragraphs of a novel)
2. Motivation: reading a leaflet with information about the health benefits of exercise
3. Planning: received the same leaflet plus completed a planning task specifying what, when, and where to exercise
4/x
November 13, 2025 at 3:38 PM
Groups:
1. Control: reading a neutral text (first three paragraphs of a novel)
2. Motivation: reading a leaflet with information about the health benefits of exercise
3. Planning: received the same leaflet plus completed a planning task specifying what, when, and where to exercise
4/x
1. Control: reading a neutral text (first three paragraphs of a novel)
2. Motivation: reading a leaflet with information about the health benefits of exercise
3. Planning: received the same leaflet plus completed a planning task specifying what, when, and where to exercise
4/x
This study investigated the impact of educational and planning strategies on exercise participation. Participants (n=248 university students) were randomly assigned to three groups. Exercise sessions were measured over the week following the intervention.
3/x
3/x
November 13, 2025 at 3:38 PM
This study investigated the impact of educational and planning strategies on exercise participation. Participants (n=248 university students) were randomly assigned to three groups. Exercise sessions were measured over the week following the intervention.
3/x
3/x
Exercise provides many health benefits and can improve fitness and appearance. Yet, many people do not exercise regularly.
2/x
2/x
November 13, 2025 at 3:38 PM
Exercise provides many health benefits and can improve fitness and appearance. Yet, many people do not exercise regularly.
2/x
2/x
Follow me @jorntrommelen for more evidence-based threads on exercise & nutrition.
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
Can sweeteners help maintain weight loss?
Large RCT investigating the impact of sweeteners on:
- weight loss
- cardiometabolic health
- gut health
Let’s break it down!
1/x
Large RCT investigating the impact of sweeteners on:
- weight loss
- cardiometabolic health
- gut health
Let’s break it down!
1/x
November 5, 2025 at 7:46 AM
Follow me @jorntrommelen for more evidence-based threads on exercise & nutrition.
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
If you think others would benefit too, please like & repost the first tweet linked below.
bsky.app/profile/jorn...
Conclusion:
Sweeteners can support long-term weight loss maintenance and may beneficially impact gut health.
Link to study:
pmc.ncbi.nlm.nih.gov/articles/PMC...
11/11
Sweeteners can support long-term weight loss maintenance and may beneficially impact gut health.
Link to study:
pmc.ncbi.nlm.nih.gov/articles/PMC...
11/11
Effect of sweeteners and sweetness enhancers on weight management and gut microbiota composition in individuals with overweight or obesity: the SWEET study
Consumption of sweeteners and sweetness enhancers (S&SEs) is a popular strategy to reduce sugar intake, but the role of S&SEs in body weight regulation and gut microbiota composition remains debated. Here, we show that S&SEs in a healthy diet ...
pmc.ncbi.nlm.nih.gov
November 5, 2025 at 7:46 AM
Conclusion:
Sweeteners can support long-term weight loss maintenance and may beneficially impact gut health.
Link to study:
pmc.ncbi.nlm.nih.gov/articles/PMC...
11/11
Sweeteners can support long-term weight loss maintenance and may beneficially impact gut health.
Link to study:
pmc.ncbi.nlm.nih.gov/articles/PMC...
11/11
A limitation is that, because commercial products were used, blinding of subjects was not possible.
10/x
10/x
November 5, 2025 at 7:45 AM
A limitation is that, because commercial products were used, blinding of subjects was not possible.
10/x
10/x