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  • Top 5 Nutrition Resources of 2020

    by David Barr | Jan 28, 2021

    It's the best of the best - the top 5 most-popular ACSM Nutrition Blogs and Resources of 2020.

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    #3 Nutrition and the Exercise Professional’s Scope of Practice


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    #2 Nutrition Resources | Comprehensive List

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  • ACSM Fit Science | January 2021

    by David Barr | Jan 26, 2021

    ACSM Certification Fit Science

    ACSM Fit Science includes recent fitness-related stories featuring the college and its members as subject matter experts. ACSM is a recognized leader among national and international media and a trusted source on sports medicine and exercise science topics. Because these stories may be written by the media, they do not necessarily reflect ACSM statements, views or endorsements. These stories are meant to share ACSM coverage with fitness professionals and inform them about what the public is reading and hearing about the field.

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  • Top 10 News Stories of 2020

    by Caitlin Kinser | Jan 26, 2021

    Each Tuesday afternoon ACSM members receive ACSM's Sports Medicine Bulletin (SMB) in their inbox. Featured in each issue is the In The News section, which highlights news articles that focus on research published in ACSM journals or that feature ACSM members as subject matter experts. We present the Top 10 most read In The News articles of 2020.

    Not an ACSM member but would like to receive SMB for these articles and more ACSM news? Become an ACSM member today.

    SMB (1)

    1. Why Running Won't Ruin Your Knees

    The New York Times | Oct. 27

    In one of her new Phys Ed columns, Gretchen Reynolds discusses new research published by ACSM member Ross Miller, Ph.D., and cites older research from Dr. Miller that was published in Medicine & Science in Sports & Exercise®.

    Could running actually be good for your knees? That idea is at the heart of a fascinating new study of the differing effects of running and walking on the knee joint.

    2. 5 Health Benefits of Stretching: Why It's So Important and How to Stretch Properly, According to Physical Therapists   

    Insider | Nov. 17

    ACSM Fellows Barbara Bushman, Ph.D., ACSM-CEP®, ACSM-EP®, ACSM-PT®, and Phil Page, Ph.D., P.T., offer insights and tips in this article.

    Any healthy workout routine should include stretching exercises. That's because stretching provides a variety of health benefits, from improving flexibility to preventing injury.

    3. Your Ultimate, Science-Backed Guide to High-Intensity Interval Training 

    Runner's World via | Oct. 27

    This article on high-intensity interval training mentions ACSM’s annual trends release and links to the Worldwide Survey of Fitness Trends for 2020 published in ACSM’s Health & Fitness Journal®.

    High-intensity interval training, or HIIT for short, was named one of the top fitness trends in the world for 2020, based on an annual survey by the American College of Sports Medicine. This super hard, super effective style of training isn’t just the “it” workout of the moment—of the 14 years ACSM has been conducting this survey, HIIT ranked in the top three spots for six consecutive years.

    4. Does Standing in Your Saddle Really Help You Power Up? | July 28

    This story discusses recent research by ACSM member Ross Wilkinson, Ph.D., that was published in the July 2020 issue of Medicine & Science in Sports & Exercise®.

    When you’re out on a ride and you see a big hill coming up, you often shift to stand in your pedals in order to tackle it. But is that increased oomph a real thing or just a placebo effect?

    5. To Strength Train Right, Trust Your Feelings 

    Outside | Nov. 11

    This piece on getting the most of resistance workouts cites and links to an ACSM position stand, related studies by ACSM Fellow Stuart Phillips, Ph.D., from McMaster University and ACSM’s Guidelines for Strength Training infographic.

    You don’t need an elaborate workout plan to get the most out of your resistance workout; you just need to tune into how you feel.

    6. Handgrip Strength Could Be a Simple Way to Predict Fall Risk

    Medscape | June 23

    This article highlights Silvia Neri’s accepted abstract for the 2020 ACSM Annual Meeting, which is now an ePoster for the ACSM 2020 Virtual Experience.

    Handgrip strength might be an effective and easy way to assess the risk for falls in older people, according to results from a new study.

    7. Intense Workouts Can Stress Immune System, Heighten Risk of Respiratory Illnesses, Coronavirus: Study

    Fox News | Aug. 18

    This article cites ACSM’s new call to action statement on COVID-19 and considerations for sports and physical activity that was published in the August issue of Current Sports Medicine Reports and includes comments from author Thomas Best, M.D., FACSM.

    Extreme exercise routines like marathon running, Crossfit and working out to exhaustion could make some individuals more vulnerable to contracting COVID-19, new research suggests.

    8. High-Impact Training Can Build Bone in Older Women

    Medscape | July 7

    In this piece, ACSM Fellow Belinda Beck, Ph.D., shares insights on the research she presented as part of ACSM’s 2020 Virtual Experience.

    Older adults, particularly postmenopausal women, are often advised to pursue low-impact, low-intensity exercise as a way to preserve joint health, but that approach might actually contribute to a decline in bone mineral density, researchers report.

    9. The Race Is on to be the Peloton of Weightlifting

    The New York Times via Chicago Tribune | Aug.25

    ACSM Fellow Michele Olson, Ph.D., offers insights in this article about a current trend in strength-training devices.

    While there are tens of millions of unemployed Americans, some are still shelling out thousands of dollars to set themselves up with home fitness equipment. These would-be barbell juggernauts have some heavy lifting to do, though.

    10. There's a Better Way to Warm Up than Stretching           

    Popular Science | Oct.13

    ACSM Fellow Dixie Stanforth, Ph.D., offer insights in this story about engaging in dynamic warmups before you start a workout.

    Anyone who played sports as a kid, or even just half-heartedly participated in gym class, may remember prefacing that activity by standing in a circle pulling on your limbs until they were well-stretched. If you’re still doing something similar today, it’s time to end your friendship with pre-workout stretches. Now dynamic warmups are your best friend.


  • Nutrient Ratios for Strength Training and More | Nutrition FAQs

    by David Barr | Jan 25, 2021

    Recovery Ratios Intermittent Fasting Nutrition ACSM
    3 Nutrition FAQs from the webinar - Nutrition and Physical Activity: The Science Works

    This part of the FAQ series covers: nutrient ratios for strength training, iron and older adults.


    Watch the Webinar on the Professional Resources Page

    Not a Member? Join Today!

    Q7: Is there any relationship between low iron, persistent, now being treated with oral supplements, with low bone mass?

    I am unaware of any specific studies demonstrating a relationship between oral iron supplementation resulting in lower bone mineral density (BMD) in athletes. One study (Harris et al., 2003), found that the impact of iron on BMD was dose and calcium intake dependent. Another study (Yang et al., 2011) found that increased iron could be a factor that slows bone formation in postmenopausal women.


    ACSM Nutrition for Exercise Science

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    Data from the National Health and Nutrition Examination Survey, 2005-2010 found that higher serum ferritin (i.e., stored iron) was significantly associated with lower femoral neck and lumbar spine BMD. (Lu et al., 2020) There are also studies implying that common supplementation strategies of iron may have negative health consequences, with the recommendation that iron supplementation only be undertaken under the supervision of a physician and only prescribed when there is a known biological deficiency. For instance, Zoller and Vogel (2004), conclude that there is an increased risk for colon cancer and other conditions that mandate careful monitoring of athletes taking daily oral iron supplements. 

    Sports Nutrition FAQ
    View Nutrition FAQs on fasting, adaptation timing and glycogen.

    A study by Mursu et al (2011) of 38,772 older women (mean age 62 years) found that those who regularly took iron supplements had a 3.9% increase in all-cause mortality. It is my opinion that there is logic to assessing any potential relationship with iron supplementation and BMD, as both iron and calcium are divalent minerals that are competitively absorbed in the proximal duodenum. A daily high dose oral supplement of iron has the potential, therefore, of diminishing the absorption of calcium sufficiently to negatively impact BMD. 

    • Harris MM, Houtkooper LB, Sanford VA, et al. Dietary iron is associated with bone mineral densityin healthy postmenopausal women. J. Nutr. 2003; 133: 3598–3602
    • Heinz Zoller, Wolfgang Vogel, Iron supplementation in athletes—first do no harm, Nutrition. 2004; 20(7-8): 615-619.
    • Lu M, Liu Y, Shao M et al. Associations of iron intake, serum iron and serum ferritin with bone mineral density in women: The National Health and Nutrition Examination Survey, 2005-2010. Calcified Tissue International 2020; 106: 232-238.
    • Mursu J, Robien K, Harnack LJ, Park K, and Jacobs DR. Dietary supplements and mortality rate in older women: The Iowa Women’s Health Study. Archives of Internal Medicine 2011; 171(18): 1625-1633.
    • Yang Q, Jian J, Abramson SB and Huang X. Inhibitory effects of iron on bone morphogenetic protein 2–induced osteoblastogenesis. J Bone Miner Res, 2011; 26: 1188-1196.

    Q8: I have some questions specifically for the older client. Where I can find more research on this information?

    • How should post-menopausal women adjust their intake to support optimal bone health?
    • How can recreational athletes who participate in activities that are 2-3 hours long, such as long bike rides, support their energy output. They are not competing, just riding long distances.
    • How does intermittent fasting affect the older recreational athlete?
    • I typically do not recommend sports drinks because they contain a lot of added sugar. Instead, I recommend my clients drink water and eat real food. If it's packaged food (easier to carry on a bicycle) the ingredients should be recognizable. Is this adequate?


    It is my impression that the biggest factor for all of your bullets is to avoid relative energy deficiency in sport (RED-S). This requires planning to assure the activity takes place when the individual is in a relatively good energy balanced state, and that blood sugar is within the normal range. The individual should also plan on having a sports beverage available to sip on so as to sustain blood sugar within the normal range during the activity. This helps to lower cortisol, which is catabolic to lean and skeletal tissue. References on RED-S are provided below.

    Note: A well-prepared sports beverage has about half the sugar content of orange juice per equal volume. Learning to sip on it rather than drink a large volume post-exercise or when thirsty is an important and effective strategy that has better outcomes than water when consumed during physical activity. I fully agree with you that liquid calories should be avoided when not exercising.

    Recovery Ratios Intermittent Fasting Nutrition ACSM
    View Nutrition FAQs on Recovery Ratios Intermittent Fasting and more.

    The result of intermittent fasting is to create a state of relative energy deficiency, so it is important to carefully review the International Olympic Committee consensus statements on the health and performance issues created with Relative Energy Deficiency in Sport (RED-S). These references, as IOC consensus statements, are publicly available (suggest doing a Google Scholar search for ‘Mountjoy RED-S’) to download and review.  Here are some references related to RED-S:

    • Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC Consensus Statement on Relative Energy Deficiency in Sport (RED-S) Br J Sports Med. doi:10.1136/ bjsports-2018-099193
    • Torstveit MK, Fahrenholtz I, Stenqvist TB, Sylta O, and Melin A. Within-Day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes. Int J Sport Nutr Exerc Metab. 2018; 28: 419-427
    • Fahrenholtz IL, Sjödin A, Benardot D, et al. Within-Day Energy Deficiency and Reproductive Function in Female Endurance Athletes. Scand J Med Sci Sports 2018; 1-8: DOI: 10.111/sms.13030.
    • Delk-Licata A, Behrens CE, Benardot D, et al. The Association Between Dietary Protein Intake Frequency, Amount, and State of Energy Balance on Body Composition in a Women’s Collegiate Soccer Team. Int J Sports Exerc Med 2019; 5(3):123. DOI:

    These papers and the book (ACSM’s Nutrition for Exercise Science) clearly describe the health and performance issues created when there is insufficient energy available to perform the physical task at hand. While there may be a temporary ‘weight’ loss, the elevation in cortisol suggests that far too much of the weight is coming from lean tissue, which compromises the very tissue the athlete is trying to improve through exercise.  In addition, cortisol is highly catabolic to bone tissue, placing the athlete at higher risk of skeletal injury (stress fracture, etc.). It is important to consider that blood sugar maintenance during the day with normal daytime activity is approximately 3 hours, and at night while asleep approximately 7 hours. Exercising when in a low blood sugar state, as these papers clearly describe, creates precisely the opposite outcomes to what the athlete is wishing to achieve.

    Chapter 10 of ACSM’s Nutrition for Exercise Science is devoted to reviewing what we know about optimizing nutrition strategies for different ages and sex. The focus on older athletes are the following health-related issues:

    • Age-related changes in body composition and the impact this has on REE;
    • Lowered capacity to quickly recover from intensive or long bouts of exercise;
    • Gradually diminishing bone mass;
    • Subtle changes in GI tract function that could influence nutrient absorption;
    • Progressively lower heat tolerance;
    • Progressive decreases in the glomerular filtration rate and renal blood flow;
    • Reduced capacity to concentrating urine, increasing urinary frequency, and, potentially, lowering fluid consumption.

    Thank you for asking these important questions.


    Q9: Based on the presenter’s previous work and also previous research that I have read, I have come to accept 3:1 to 4:1 as the optimal carbohydrate to protein ratio for immediate post-workout glycogen replenishment. But in the presentation on 19 November a 1:1 carbohydrate to protein ratio was presented. Is this based on updated research or has something else changed. I am particularly interested in glycogen replenishment after intense resistance training for hypertrophy (or strength) with, for example, a duration of less than 60 minutes 3-4 days per week and assuming an optimal (surplus) calorie intake and 55-60% carbohydrate, 18-20% protein and 20-25% fat.

    Apologies for having left his impression. The key point to consider is that there is evidence that both carbohydrate and protein consumption post exercise are important. The general recommendation is that more carbohydrate (g/kg) should be consumed post exercise than protein, but the data on the specific ratio are, as yet, categorized as only ‘fair’ or ‘limited’ (see reference below: Thomas et al., 2016). It has been summarized from these studies that consuming about 20 to 30 g protein, or ~10g of essential amino acids post-exercise results in increased whole body and muscle protein synthesis as well as improved nitrogen balance.

    Please note the large range in the recommendation (i.e., 20 to 30 g). It has also been found that co-ingestion of carbohydrate with protein found no significant improvement on muscle glycogen synthesis, as this is primarily a carbohydrate only factor.  It has been determined that the highest rate of muscle glycogen synthesis occurs when large amounts of carbohydrate (1.0–1.85 g/kg/h) are consumed immediately post-exercise and at 15-minute intervals thereafter, for up to 5 hours post-exercise. (Please note the range in carbohydrate recommendation.)

    The total daily recommended protein intake is approximately the same (1.2 to 2.0 g/kg/d) as the post-exercise hourly intake of carbohydrate, suggesting that post-exercise carbohydrate needs are significantly higher post exercise. To put this into relative perspective, the recommendation for 30 g of protein post exercise for a 150 lb (68 kg) athlete represents about 0.44 g/kg protein, with the recommendation for carbohydrate significantly higher. These data also suggest differential effects, with protein consumption focusing primarily on muscle soreness and recovery, with carbohydrate consumption focusing primarily on glycogen recovery.

    Clearly, athletes need carbohydrate, protein, and fluids post exercise, and the judgement on the relative amount provided should be based on the degree to which glycogen depletion and muscle soreness have occurred, which are factors likely related to exercise duration and intensity, and fluid volume/quality consumed during exercise.

    As a side note, since energy balance is likely to be low post exercise, a relatively high protein and low carbohydrate intake post-exercise is likely to result in at least a portion of the protein being used to satisfy energy recovery needs. As this can only occur when protein is denitrogenated, the resultant higher blood urea nitrogen is likely to result in higher urine production and inhibit a speedier return to a well-hydrated state.

    Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–68.

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    ACSM Fellow Dan Benardot, Ph.D., DHC, R.D., L.D., is Professor Emeritus at Georgia State University, and Professor of Practice in the Center for the Study of Human Health at Emory University. He is the author of the popular book ACSM’s Nutrition for Exercise Science.

  • 5 Best Fitness Professional Resources of 2020

    by David Barr | Jan 21, 2021

    It's the best of the best - the top 5 most-popular ACSM Fitness Professional Resources of 2020.

    ACSM Nutrition FAQs

    #5 Nutrition Resources

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    #4 COVID-19 Reopening and Return to Play Resources

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