The running science “nerd alert”
from Thomas Solomon PhD


September 2022
Each month we compile a short list of recently-published papers (full list here) in the world of running science and break them into bite-sized chunks so you can digest them as food for thought to help optimise your training. To help wash it all down, we even review our favourite beer of the month.
Welcome to this month's instalment of our “Nerd Alert”. We hope you enjoy it.
Welcome to this month's instalment of our “Nerd Alert”. We hope you enjoy it.
Click the title of each article to reveal our summary.
Full paper access: click here
What was the hypothesis or research question?
The factors that influence the inter-individual (between-person) variability in the response to resistance training are not known but increased muscle capillarization might enhance strength gains following resistance training. Therefore, the purpose of this study was to examine the impact of “preconditioning” with aerobic training (which is known to increase increased muscle capillarization) on changes in muscle hypertrophy (aka muscle mass) and satellite cell content and activation following resistance training (NOTE: satellite cells are muscle stem cells from which mature muscle cell grow). The authors hypothesised that 6-weeks of “pre-conditioning” with aerobic training (to increase capillarization) would boost resistance training-induced increases in muscle hypertrophy and satellite cell content and activation compared to resistance training alone.” .
What did they do to test the hypothesis or answer the research question?
— They recruited 14 young (~21 years old) males (8) and females (6) volunteers who had never resistance trained and were aerobically unfit (V̇O2max ~39 mL/min/kg measured during bilateral [both legs] cycling).

Table of subject characteristics.
— Subjects completing the intervention served as their own control with only one leg being aerobically trained (AC+RT) for 6-weeks and then both legs being resistance exercise trained (RT). For 6-weeks subjects performed unilateral (one-legged) cycling at 50% of their one-leg V̇O2max 3 times per a week for 45 minutes a session. Two weeks after the aerobic conditioning, subjects performed bilateral (both legs) strength training 3 times per week for 10 weeks consisting of squats, leg press, leg extension, hamstring curls, and calf raises with most exercises at 70-80% of their 1 repetition max for 3 sets of 10-12 repetitions. They were also given 25g of whey protein post resistance training.
— Functional outcomes measurements included 1 repetition max for squat, leg extension, and leg press to see whether the resistance training worked (increased muscle strength) and one-legged cycling V̇O2max.
— Mechanistic measurements included immunofluorescent staining of muscle biopsies to identify fibre type-specific muscle cross-sectional area, satellite cell content and activation, and capillary density.
— Statistical analysis included two-way repeated measures to compare pre vs. post-intervention changes in variables between the AC+RT (aerobic then resistance) and RT (resistance training) only conditions. To examine inter-individual (between-person) variability and identity “high” vs “low” responders, individual subject changes in satellite cell content, cross-sectional area, and capillary density were ranked in order of magitude.
What did they find?
— The interventions worked as desired. Firstly, aerobic conditioning (one-legged cycling) increased aerobic capacity (V̇O2max) of only the working leg and not the other leg, and then fell during the 10 weeks of resistance training.

Changes in 1-legged V̇O2max
Secondly, resistance training improved muscle strength as measured by increases in 1RM squat and leg press, and increases in fat-free mass (a crude biomarker for muscle mass).

Changes in muscle strength.
Double leg, 1-repetition max strength measurements for squat and leg-press post AC and post RT. Data are expressed as box and whisker plots, where + represents the mean, horizontal lines represent the first quartile (bottom), median (middle), and third quartile (top), and error bars represent the minimum (bottom) and maximum (top) values. ‡ represents P≤0.05, difference from post AC. # represents P≤0.05, difference from baseline.
— Overall, resistance training increased type I (slow) and type II (fast) fibre cross-sectional area. But, when legs were analyzed separately, AC+RT (aerobic then resistance training) increased type I, type II, and mixed-fibre cross-sectional area, whereas the RT (resistance training) only leg tended to increase type II but not type I or mixed-fibre cross-sectional area.
— Resistance training also increased satellite cell content, activation, and differentiation, but AC+RT more greatly increased type I satellite cell content (total and quiescent, aka inactive) than RT alone.
— Subjects with the greatest capillary-to-fibre perimeter exchange index (i.e. a proxy for higher muscle capillarization) before resistance training had the greatest increase in CSA following resistance training. Furthermore, type II fiber capillarization was significant related to the resistance training-induced change in type II fiber cross-sectional area (moderate sized correlation coefficient: r = 0.35).
Inter-individual (between-person) variability in changes in muscle fibre measures.
— Authors concluded that 6 weeks of aerobic exercise training that increases V̇O2max prior to RT can boost resistance training-induced muscle strength and cellular adaptions and that this effect is associated with increases in muscle capillarization. Though we must add that this is in young and healthy but previously untrained folks.
What were the strengths?
— Each subject served as their own control with one leg performing the AC+RT and the other only performing the RT. This is a clever within-subject design that negates the need for a separate control group.
— The interventions did as they were supposed to. Increases aerobic capacity (and capillarization) and increased strength.
— To help maximise muscle protein synthesis, the authors provided subjects with 25 g of whey protein isolate (including 2.7 g leucine) after each resistance training session.
— In accordance with open science practice, the authors supply their raw data in an open-access Supplemental file.
What were the weaknesses?
— The study did not include single leg strength measures. It would have been nice to see direct evidence that the AC+RT group improved single leg strength in addition to the markers of hypertrophy and satellite cell content/activation.
— The most important comparisons are all associations based on correlations. The study design did not allow the authors to directly test whether capillarization augments the increase in the cross-sectional area of muscle fibres (or better yet strength).
— Although the authors report that “Random assignment (based on leg dominance) determined which leg would complete the AC protocol while the other would remain untrained”, this statement implies that subjects used their dominant leg for the intervention and, therefore, the leg was not randomly assigned.
— While post-session whey protein was provided to help maximise muscle protein synthesis, it is unclear whether subjects were in energy balance nor what macronutrient composition their diets were during the study — this is important because energy availability, carbohydrate availability, and total daily protein intake can influence the outcomes measured. It is also unclear whether the training sessions were completed in a fed or fasted state — this is important because training adaptations are influenced by the prandial state.
Are the findings useful in application to training/coaching practice?
For endurance athletes, no. (But, the findings do suggest that an endurance athlete might get a greater strength gain from resistance training than a non-endurance athlete because of their high level of muscle capillarity and V̇O2max.)
For strength athletes, yes.
Many strength athletes shy away from aerobic conditioning for fear of getting weak like endurance athletes. But, this study suggests that aerobic conditioning may actually help the muscle adapt better to strength training. This idea isn’t new and the fellas at Stronger by Science have written about how not doing aerobic training may be holding strength athletes back. All that said, we are mindful that this study included previously untrained folks so we cannot extrapolate to the same outcomes being found in trained athletes.
What is our Rating of Perceived Scientific Enjoyment?
RP(s)E = 7 out of 10.

The factors that influence the inter-individual (between-person) variability in the response to resistance training are not known but increased muscle capillarization might enhance strength gains following resistance training. Therefore, the purpose of this study was to examine the impact of “preconditioning” with aerobic training (which is known to increase increased muscle capillarization) on changes in muscle hypertrophy (aka muscle mass) and satellite cell content and activation following resistance training (NOTE: satellite cells are muscle stem cells from which mature muscle cell grow). The authors hypothesised that 6-weeks of “pre-conditioning” with aerobic training (to increase capillarization) would boost resistance training-induced increases in muscle hypertrophy and satellite cell content and activation compared to resistance training alone.” .

— They recruited 14 young (~21 years old) males (8) and females (6) volunteers who had never resistance trained and were aerobically unfit (V̇O2max ~39 mL/min/kg measured during bilateral [both legs] cycling).

— Functional outcomes measurements included 1 repetition max for squat, leg extension, and leg press to see whether the resistance training worked (increased muscle strength) and one-legged cycling V̇O2max.
— Mechanistic measurements included immunofluorescent staining of muscle biopsies to identify fibre type-specific muscle cross-sectional area, satellite cell content and activation, and capillary density.
— Statistical analysis included two-way repeated measures to compare pre vs. post-intervention changes in variables between the AC+RT (aerobic then resistance) and RT (resistance training) only conditions. To examine inter-individual (between-person) variability and identity “high” vs “low” responders, individual subject changes in satellite cell content, cross-sectional area, and capillary density were ranked in order of magitude.

— The interventions worked as desired. Firstly, aerobic conditioning (one-legged cycling) increased aerobic capacity (V̇O2max) of only the working leg and not the other leg, and then fell during the 10 weeks of resistance training.


Double leg, 1-repetition max strength measurements for squat and leg-press post AC and post RT. Data are expressed as box and whisker plots, where + represents the mean, horizontal lines represent the first quartile (bottom), median (middle), and third quartile (top), and error bars represent the minimum (bottom) and maximum (top) values. ‡ represents P≤0.05, difference from post AC. # represents P≤0.05, difference from baseline.
— Resistance training also increased satellite cell content, activation, and differentiation, but AC+RT more greatly increased type I satellite cell content (total and quiescent, aka inactive) than RT alone.
— Subjects with the greatest capillary-to-fibre perimeter exchange index (i.e. a proxy for higher muscle capillarization) before resistance training had the greatest increase in CSA following resistance training. Furthermore, type II fiber capillarization was significant related to the resistance training-induced change in type II fiber cross-sectional area (moderate sized correlation coefficient: r = 0.35).


— Each subject served as their own control with one leg performing the AC+RT and the other only performing the RT. This is a clever within-subject design that negates the need for a separate control group.
— The interventions did as they were supposed to. Increases aerobic capacity (and capillarization) and increased strength.
— To help maximise muscle protein synthesis, the authors provided subjects with 25 g of whey protein isolate (including 2.7 g leucine) after each resistance training session.
— In accordance with open science practice, the authors supply their raw data in an open-access Supplemental file.

— The study did not include single leg strength measures. It would have been nice to see direct evidence that the AC+RT group improved single leg strength in addition to the markers of hypertrophy and satellite cell content/activation.
— The most important comparisons are all associations based on correlations. The study design did not allow the authors to directly test whether capillarization augments the increase in the cross-sectional area of muscle fibres (or better yet strength).
— Although the authors report that “Random assignment (based on leg dominance) determined which leg would complete the AC protocol while the other would remain untrained”, this statement implies that subjects used their dominant leg for the intervention and, therefore, the leg was not randomly assigned.
— While post-session whey protein was provided to help maximise muscle protein synthesis, it is unclear whether subjects were in energy balance nor what macronutrient composition their diets were during the study — this is important because energy availability, carbohydrate availability, and total daily protein intake can influence the outcomes measured. It is also unclear whether the training sessions were completed in a fed or fasted state — this is important because training adaptations are influenced by the prandial state.

For endurance athletes, no. (But, the findings do suggest that an endurance athlete might get a greater strength gain from resistance training than a non-endurance athlete because of their high level of muscle capillarity and V̇O2max.)
For strength athletes, yes.
Many strength athletes shy away from aerobic conditioning for fear of getting weak like endurance athletes. But, this study suggests that aerobic conditioning may actually help the muscle adapt better to strength training. This idea isn’t new and the fellas at Stronger by Science have written about how not doing aerobic training may be holding strength athletes back. All that said, we are mindful that this study included previously untrained folks so we cannot extrapolate to the same outcomes being found in trained athletes.

RP(s)E = 7 out of 10.














That is all for this month's nerd alert. We hope to have succeeded in helping you learn a little more about the developments in the world of running science. If not, we hope you enjoyed a nice beer…
If you find value in our nerd alerts, please help keep them alive by sharing them on social media and buying us a beer at buymeacoffee.com/thomas.solomon. For more knowledge, join Thomas @thomaspjsolomon on Twitter, follow @veohtu on Facebook and Instagram, subscribe to Thomas’s free email updates at veothu.com/subscribe, and visit veohtu.com to check out Thomas’s other articles, nerd alerts, free training tools, and his Train Smart Framework. To learn while you train, you can even listen to Thomas’s articles by subscribing to the Veohtu podcast.
Until next month, stay nerdy and keep empowering yourself to be the best athlete you can be...
If you find value in our nerd alerts, please help keep them alive by sharing them on social media and buying us a beer at buymeacoffee.com/thomas.solomon. For more knowledge, join Thomas @thomaspjsolomon on Twitter, follow @veohtu on Facebook and Instagram, subscribe to Thomas’s free email updates at veothu.com/subscribe, and visit veohtu.com to check out Thomas’s other articles, nerd alerts, free training tools, and his Train Smart Framework. To learn while you train, you can even listen to Thomas’s articles by subscribing to the Veohtu podcast.
Until next month, stay nerdy and keep empowering yourself to be the best athlete you can be...
Everyday is a school day.
Empower yourself to train smart.
Think critically. Be informed. Stay educated.
Empower yourself to train smart.
Think critically. Be informed. Stay educated.
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About the authors:
Matt and Thomas are both passionate about making science accessible and helping folks meet their fitness and performance goals. They both have PhDs in exercise science, are widely published, have had their own athletic careers, and are both performance coaches alongside their day jobs. Originally from different sides of the Atlantic, their paths first crossed in Copenhagen in 2010 as research scientists at the Centre for Inflammation and Metabolism at Rigshospitalet (Copenhagen University Hospital). After discussing lots of science, spending many a mile pounding the trails, and frequent microbrew pub drinking sessions, they became firm friends. Thomas even got a "buy one get one free" deal out of the friendship, marrying one of Matt's best friends from home after a chance encounter during a training weekend for the CCC in Schwartzwald. Although they are once again separated by the Atlantic, Matt and Thomas meet up about once a year and have weekly video chats about science, running, and beer. This "nerd alert" was created as an outlet for some of thehundreds of scientific papers craft beers they read drink each month.
Matt and Thomas are both passionate about making science accessible and helping folks meet their fitness and performance goals. They both have PhDs in exercise science, are widely published, have had their own athletic careers, and are both performance coaches alongside their day jobs. Originally from different sides of the Atlantic, their paths first crossed in Copenhagen in 2010 as research scientists at the Centre for Inflammation and Metabolism at Rigshospitalet (Copenhagen University Hospital). After discussing lots of science, spending many a mile pounding the trails, and frequent microbrew pub drinking sessions, they became firm friends. Thomas even got a "buy one get one free" deal out of the friendship, marrying one of Matt's best friends from home after a chance encounter during a training weekend for the CCC in Schwartzwald. Although they are once again separated by the Atlantic, Matt and Thomas meet up about once a year and have weekly video chats about science, running, and beer. This "nerd alert" was created as an outlet for some of the
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