Jorn Trommelen, PhD
@jorntrommelen.bsky.social
Assistant professor. Muscle Metabolism.
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
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
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)
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
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 3:37 PM
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
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
Strengths of this study include its long study duration (12 months), large multi-national sample size (379 participants), inclusion of multiple sweeteners and commercial products, and the replacement of sugar with sweeteners within a generally healthy diet.
9/x
9/x
November 5, 2025 at 7:45 AM
Strengths of this study include its long study duration (12 months), large multi-national sample size (379 participants), inclusion of multiple sweeteners and commercial products, and the replacement of sugar with sweeteners within a generally healthy diet.
9/x
9/x
Interpretation:
This large-scale trial indicates that replacing sugar with sweeteners helps maintain weight loss.
Moreover, the use of sweeteners did not adversely affect cardiometabolic health and improved the gut microbiome.
8/x
This large-scale trial indicates that replacing sugar with sweeteners helps maintain weight loss.
Moreover, the use of sweeteners did not adversely affect cardiometabolic health and improved the gut microbiome.
8/x
November 5, 2025 at 7:45 AM
Interpretation:
This large-scale trial indicates that replacing sugar with sweeteners helps maintain weight loss.
Moreover, the use of sweeteners did not adversely affect cardiometabolic health and improved the gut microbiome.
8/x
This large-scale trial indicates that replacing sugar with sweeteners helps maintain weight loss.
Moreover, the use of sweeteners did not adversely affect cardiometabolic health and improved the gut microbiome.
8/x
Key findings after the 12 months:
• The sweeteners group maintained greater weight loss (1.6±0.7 kg).
• The sweeteners group showed beneficial changes in the gut microbiome.
• No significant differences between the groups were observed for cardiometabolic health markers
• The sweeteners group maintained greater weight loss (1.6±0.7 kg).
• The sweeteners group showed beneficial changes in the gut microbiome.
• No significant differences between the groups were observed for cardiometabolic health markers
November 5, 2025 at 7:45 AM
Key findings after the 12 months:
• The sweeteners group maintained greater weight loss (1.6±0.7 kg).
• The sweeteners group showed beneficial changes in the gut microbiome.
• No significant differences between the groups were observed for cardiometabolic health markers
• The sweeteners group maintained greater weight loss (1.6±0.7 kg).
• The sweeteners group showed beneficial changes in the gut microbiome.
• No significant differences between the groups were observed for cardiometabolic health markers
They were then assigned to a 10-month healthy diet phase:
• The sugar group was allowed <10% of total energy from sugar.
• The sweetener group replaced sugar with sweeteners as much as possible
6/x
• The sugar group was allowed <10% of total energy from sugar.
• The sweetener group replaced sugar with sweeteners as much as possible
6/x
November 5, 2025 at 7:44 AM
They were then assigned to a 10-month healthy diet phase:
• The sugar group was allowed <10% of total energy from sugar.
• The sweetener group replaced sugar with sweeteners as much as possible
6/x
• The sugar group was allowed <10% of total energy from sugar.
• The sweetener group replaced sugar with sweeteners as much as possible
6/x
This RCT examined the long-term effects of sweeteners on weight loss maintenance, cardiovascular health, and the gut microbiome.
Participants (341 adults and 38 children) with overweight or obesity first followed a two-month weight-loss diet (>5% reduction in body weight).
5/x
Participants (341 adults and 38 children) with overweight or obesity first followed a two-month weight-loss diet (>5% reduction in body weight).
5/x
November 5, 2025 at 7:44 AM
This RCT examined the long-term effects of sweeteners on weight loss maintenance, cardiovascular health, and the gut microbiome.
Participants (341 adults and 38 children) with overweight or obesity first followed a two-month weight-loss diet (>5% reduction in body weight).
5/x
Participants (341 adults and 38 children) with overweight or obesity first followed a two-month weight-loss diet (>5% reduction in body weight).
5/x
Some studies have suggested that sweeteners may be ineffective for weight management or could negatively affect gut health.
The evidence is conflicting, likely due to differences in study design.
4/x
The evidence is conflicting, likely due to differences in study design.
4/x
November 5, 2025 at 7:43 AM
Some studies have suggested that sweeteners may be ineffective for weight management or could negatively affect gut health.
The evidence is conflicting, likely due to differences in study design.
4/x
The evidence is conflicting, likely due to differences in study design.
4/x