Exploring Exercise Physiology: Eccentrics, Concentrics, and Weighted Vests

In tonight’s episode of Iron Culture, Eric Trexler and Eric Helms discuss various topics related to fitness, training, and research. They share personal updates, including the toll that Helms' intense training regimen is taking on his face. The discussion then shifts to the upcoming NFL combine, highlighting the impressive athletic feats expected from past combine participants. In the main segment of the show, Trexler and Helms discuss the nuances of lengthened-biased training research – more specifically, why we shouldn’t give up on the strategy just because a few studies reporting non-significant results have come along. In this conversation, Trexler and Helms explore the concept of sampling error in research, emphasizing the importance of understanding some foundational statistical concepts and the need for several studies to draw reliable conclusions. They explore the challenges of uncertainty in evidence-based practice, the balance to strike between mechanistic and empirical approaches to understanding exercise and nutrition, and the resistance to change in learning. Finally, they engage in a rapid-fire Q&A session addressing a handful of fitness-related questions.

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Time Stamps:

00:00 Introduction and why Trexler is worried about Helms

6:40 Q&A NFL Combine analysis

Trexler 2017 Fat-Free Mass Index in NCAA Division I and II Collegiate American Football Players https://pubmed.ncbi.nlm.nih.gov/27930454/ 

13:18 Getting into the science with Helms’ upcoming MASS article on long muscle length training

Burke 2006 "Fat adaptation" for athletic performance: the nail in the coffin? https://pubmed.ncbi.nlm.nih.gov/16357078/

Nunes 2022 Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults https://pubmed.ncbi.nlm.nih.gov/35187864/

Larsen 2024 The effects of hip flexion angle on quadriceps femoris muscle hypertrophy in the leg extension exercise https://pubmed.ncbi.nlm.nih.gov/39699974/

Gschneider 2024 The effects of lengthened-partial range of motion resistance training of the limbs on arm and thigh muscle cross-sectional area https://sportrxiv.org/index.php/server/preprint/view/485/version/624

Wolf 2025 Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals https://pubmed.ncbi.nlm.nih.gov/39959841/

Kassiano 2022 Does Varying Resistance Exercises Promote Superior Muscle Hypertrophy and Strength Gains? A Systematic Review https://pubmed.ncbi.nlm.nih.gov/35438660/

Pedrosa 2023 Training in the Initial Range of Motion Promotes Greater Muscle Adaptations Than at Final in the Arm Curl https://pubmed.ncbi.nlm.nih.gov/36828324/

29:59 Simulating a large lengthened-bias training dataset

42:28 Some points from Trexler

Trexler 2019 Acute Effects of Citrulline Supplementation on High-Intensity Strength and Power Performance: A Systematic Review and Meta-Analysis https://pubmed.ncbi.nlm.nih.gov/30895562/

1:02:56 Mechanisms vs experimental trials (uncertainty)

1:10:15 Using Large Language Models for statistical analysis (in R)

1:21:01 Q&A Rapid fire 1: Work and energy expenditure during eccentric contractions  

1:23:22 Q&A Rapid fire 2: Waited vest upsides and downsides

1:25:47 Q&A Rapid fire 3: Protein recommendations for individuals who don’t train their entire body

1:29:20 Q&A Rapid fire 4: Sprint cycling for quad hypertrophy

1:35:04 Wrapping up

See the entire MASS team speak at the Sports Nutrition Association Annual Conference https://sportsnutritionassociation.com/sna-annual-2025-conference/