In This Section:

  • Active Voice | Eccentric Exercise as a Potent Prescription for Muscle Weakness after Joint Injury

    by Greg Margason | Jul 11, 2023

    Eccentric Exercise as a Potent Prescription for Muscle Weakness after Joint InjuryMuscle weakness is difficult to treat after a traumatic joint injury as it stems from a multifaceted interplay of neurological and morphological processes that disrupt the muscle's communication and regulation. Data from a large clinical database showed that four out of five patients who engage in anterior cruciate ligament rehabilitation (one of the most common therapeutic programs) leave with strength levels well below clinical recommendations. To improve this situation, rehabilitation specialists need to think beyond conventional forms of exercise prescription, as it is clear that the current treatment approaches fail to adequately restore muscle strength. In our review paper, published in Exercise and Sport Sciences Reviews (ESSR), we propose a novel framework for an exercise prescription in muscle recovery that is often overlooked. 

    Eccentric contractions (also known as lengthening contractions) offer a potent solution for muscle recovery by uniquely stimulating the nervous system and cellular signaling pathways that promote tissue health and growth. Our research, along with others, has demonstrated the power of an exercise prescription emphasizing eccentric contractions to effectively enhance neural drive and cellular signaling, which are responsive to muscle stretch and repetitive lengthening. 

    Despite its potential, there is still reluctance in the clinical community to adopt eccentric exercise due to its association with injury. This dogma is due, in large part, to misinterpreted benchtop models that often involve extreme conditions that do not accurately represent the clinical scenario (e.g., the removal of the distal point of long-tendon from the bone for experimental purposes or animals that are exercised with the intent to cause injury). We previously reported that experiments that use clinically translational doses of eccentric exercise (e.g., 15 minutes) have shown its safety and effectiveness. 

    Insufficient strength recovery is associated with various negative outcomes, including increased risk of re-injury, early joint degeneration, and reduced physical activity levels. To counteract this situation, clinicians must prioritize exercises that target the underlying causes of muscle weakness. Eccentric exercise achieves this by maintaining muscle communication through neural pathways less affected by the initial injury. It also engages essential stretch-sensing properties of the muscle, which convert mechanical stress into responses that promote muscle growth. To this point, we and others have found that training with eccentric contractions improves the magnitude and firing rate of alpha-motoneurons, resulting in greater strength recovery and knee movement profiles in those with a significant history of joint injury relative to concentrically treated patients. 

    Exploring alternative rehabilitation approaches that treat the underlying causes of muscle weakness is key to promoting more effective outcomes. Through our review paper, we aim to stimulate dialogue and reflection regarding current practices and the safe use of eccentric contractions to enhance muscle recovery. We encourage clinicians to responsibly consider the inclusion of isolated lengthening exercises to address the various factors that degrade muscle health. The review provides a series of original clinical articles that offer protocols as guidelines for development. 

    Lindsey Lepley
    Lindsey Lepley, Ph.D.
    , is an associate professor of athletic training, director of the Comparative Orthopaedic Rehabilitation Laboratory (CORL), and co-director of the Orthopedic Rehabilitation & Biomechanics Laboratory (ORB) at the University of Michigan School of Kinesiology. Her research focuses on elucidating the mechanisms that regulate skeletal muscle strength, activation, and structure after traumatic joint injury to establish interventions that optimize muscle recovery. To advance clinical practice, her research group utilizes noninvasive animal injury models and human subject research to design, test, and translate new sports medicine strategies from conception to practice. 

    Viewpoints presented in ACSM Bulletin commentaries reflect opinions of the authors and do not necessarily represent positions or policies of ACSM. Active Voice authors who have received financial or other considerations from a commercial entity associated with their topic must disclose such relationships at the time they accept an invitation to write for the ACSM Bulletin. 

  • The 2022 Journal Impact Factor: Continuing Changes and the Lingering Effects of COVID-19

    by Caitlin Kinser | Jul 06, 2023

    cover art for 5 of ACSM's journalsIn this space last year, I provided some explanation of the Journal Impact Factor (JIF), the journal metric released annually by Clarivate Analytics as part of the Journal Citation Reports (JCR). This year provides an opportunity to address the changes that Clarivate have imposed over the past three years and how macrotrends in scientific publishing have affected journal metrics. 

    From 1975 to 2019, the JIF was calculated using the same data definitions and formula. The great advantage of this consistency was that it enabled every journal to make relatively accurate year-to-year comparisons, and easily identify the variables that may have driven the JIF up or down. Consequently, editorial strategies were easier to develop and assess. 

    2020 Journal Impact Factor: Introducing “Early Access” 

    This all came to a somewhat crashing halt with the release of the 2020 JIFs. As communicated by Clarivate, the 2020 JIF would see the introduction of “Early Access” content to the JIF formula, though 2020 would be a transition year. “Early Access” content, a finalized version of an article not yet published in an issue, could now be indexed in Web of Science and contribute to the JIF formula. Complicating this was that a small subset of journals and publishers had participated in a two-year trial prior to 2020. Clarivate had to come up with a way to accommodate the citations that had been generated by “Early Access” content without giving journals that had participated in the pilot an unprecedented advantage. 

    The 2020 JIF formula would include citations from “Early Access” content in the numerators of any journals whose content has been cited during the pilot, but would not include “Early Access” content in the denominator of journals that published “Early Access” until the articles had appeared in an issue. There was an enormous amount of debate at the time over how this would skew JIF rankings, and to what extent this was to the advantage of journals that published both “Early Access” content and exhibited a relatively high rate of self-citation. Most publishers anticipated that that 2020 JIFs would experience some level of inflation, solely due to the introduction of “Early Access” content into the pipeline of citations. 

    Instead, any affect the “Early Access” content had on JIFs was completely overwhelmed by the far more extensive impact of a boom in published research that was driven directly and indirectly by COVID-19. Scientific output increased across all specialties in 2020, and the more articles being published, the more citations are being entered into the scientific literature. For editors, it was a rollercoaster ride of excitement when the journals’ 2020 JIF was 20% higher than 2019, and then the realization that this same growth had occurred for all competing journals as well. For most journals, regardless of the improvement in JIF, their rankings remained largely the same. 

    2021 Journal Impact Factor: Outliers Abound 

    The 2021 JIF ended the “Early Access” transition period, and “Early Access” content was now fully incorporated into the JIF formula. Again, there was an expectation from publishers that the JIFs would now largely normalize; however, COVID-19 was still having a tremendous impact on the publishing landscape. Although overall output had begun to slow by the end of 2021, citation activity remained high, and on average we saw JIF remain static. However, in some subjects, citation outliers drove some journal JIFs into a second wave of growth. Analysis revealed that COVID-related review articles with straightforward titles, such as “COVID and Pregnancy” or “Coronavirus and Hypertension” received citations far above average. In some cases, one of these articles alone could drive the Impact Factor 15%-20% higher. 

    2022 Journal Impact Factors: The End of the COVID Bump and Welcome ESCI Journals 

    If 2020 and 2021 JIFs had been inflated by the unusually high publication outputs in those years, the 2022 JIF represented a reset of sorts. JIFs returned to their 2019 numbers driven down by two primary factors: First, as scientific output decreased, the number of citations in the pipeline decreased and numerators dropped, and second, the increased output of both 2020 and 2021 were now being reflected for the first time in the denominator. Across the Wolters Kluwer (ACSM's publishing partner) portfolio, JIFs fell by an average of 7.3% (0.43 lower) than 2021 JIFs. If there was any concern that this was limited to Wolters Kluwer, it’s important to note that average rankings rose slightly by 0.1 place. We can assume that this means that the JIF deflation affected almost every publisher across every category. 

    Confusing comparison to JIFs of years past, the 2022 JIFs also were displayed to only one decimal place (as opposed to the three previously displayed). Since JIFs were rounded to the nearest tenth, it means that the differences in JIF from 2021 to 2022 could have a margin of error of 0.054. Also, this new change in JIF precision almost certainly will result in the introduction of ties moving forward – changing the methodology by which Clarivate will determine category rankings. 

    Significantly, Clarivate also awarded journals that had been indexed in the Emerging Sources Citation Index (ESCI) JIFs for the first time. In total, this means that almost 9,000 journals will be receiving a JIF for the first time (8% more open access journals, and 5% more journals from south of the equator). However, ESCI journals will not receive category rankings in the 2022 JCR.  

    2023 Journal Impact Factors: About Those Rankings 

    In next year’s JCR, all the different database rankings (ESCI, SCIE, and SSCI) will be combined into unified categories. In the past, for example, a nursing journal might be in both SCIE and SSCI, receiving a single JIF, but two distinct rankings for each database. Another nursing journal may have been in ESCI, receiving a JIF, but no ranking. In 2023, there will be a single set of rankings for each category, regardless of the database(s) in which the journal is indexed. The addition of ESCI journals may have a significant impact on which quartile SCIE-indexed journals may find themselves. It also begs the question of why ESCI continues to exist as a separate database. 

    Optimistically, I hope that the 2023 JCR reflects the last changes we will see to how JIF is both calculated and displayed for the near future – but I suspect that Clarivate may have opened a Pandora’s box of complications, which will be marked by a series of adjustments and overcorrections. In Clarivate’s own words, they have made some of these changes to de-emphasize the JIF, and force journals to consider other metrics, such as the Journal Citation Indicator (JCI). It remains to be seen if journals themselves will become so exasperated by Clarivate’s changes to the JIF that we will finally begin to discuss a journal’s Eigenfactor Score – in my opinion, the best journal metric ever devised! 

    Duncan MacRae is the director, Editorial Strategy and Publishing Policy for Wolters Kluwer, one of the world’s foremost publishers of medical, nursing and allied health journals. In this role, Duncan oversees the development and implementation of editorial policies followed by journals in the Lippincott and Medknow imprints. In addition, he works with a portfolio of editorial service providers to assist our society partners in achieving their strategic goals.

  • Alzheimer’s and Exercise: What Do We Know, and What Can We Do?

    by Greg Margason | Jun 28, 2023

    ACSM AlzheimersAuthor's note: This blog post is based in large part upon “Alzheimer’s Disease and Physical Activity” published in ACSM’s Health & Fitness Journal and authored by Barbara Bushman, ACSM, ACSM-CEP, ACSM-EP, ACSM-CPT, and Madison Pullen, ACSM-EP — a more in-depth piece for readers interested in the nexus of Alzheimer’s and exercise. 

    Alzheimer’s disease is “an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to carry out the simplest tasks”; it is also the most common type of dementia in older adults, representing 60-80% of dementia cases. Approximately 6 million Americans are living with Alzheimer’s disease. 

    Alzheimer’s is characterized by a number of physical changes in the brain, including the accumulation of abnormal clumps of tissue called amyloid plaques and fibrous accumulations known as tau tangles. Connections between neurons also appear to decrease in number. In later stages, the brain begins to shrink.  

    These physical alterations correspond to changes in memory, personality, and sensory processing, among other effects, eventually leading to the person becoming incapable of communication and completely reliant on others for their needs. 

    As for the root causes of the condition, there are likely a number of factors, including genetic predisposition, environmental factors, and matters of lifestyle. More on this last category in a moment. 

    Staying active 

    Those who live a sedentary lifestyle are more at risk of developing Alzheimer’s — potentially actionable information for exercise professionals. Further, people who spend their leisure time pursuing various forms of physical activity seem to be less at risk of developing Alzheimer’s than their peers. However, the situation is still murky — it isn’t necessarily clear whether the physical activity itself is in some way protective or rather that other factors involved in the activity, like social interaction, had more of an effect. Other studies suggest that exercise alone, particularly if begun late in life, may not be protective.

    Fortunately, attending fitness classes and working one on one with a personal trainer cover both the physical and social bases described above. We certainty can’t say that partnering with a certified exercise professional for regular fitness sessions will reduce the risk of developing Alzheimer’s, but the accumulated benefits of professionally supervised exercise are a major incentive in and of themselves. Pursuing such training seems like a win-win. 

    Assisting clients with Alzheimer’s 

    When building a routine either for a client with Alzheimer’s or one who is concerned about Alzheimer’s prevention, you might consider a number of factors, including the most effective exercise modalities and some of the safety concerns unique to this population. 

    An important first step, as recommended by the current edition of ACSM's Guidelines for Exercise Testing and Prescription, is to perform exercise testing. We must thoroughly understand our clients’ baseline capabilities before we send them off on an exercise prescription. Likewise, it’s best to be in contact with your client’s health care team as well as their family members to better understand their individual case. 

    Once you’ve established your client’s abilities, what exercise modalities should you pursue? Since Alzheimer’s shares risk factors with cerebrovascular diseases, aerobic exercise may be helpful. However, consider a combined approach of aerobic exercise, resistance training, and flexibility work. Bushman and Pullen provide a handy table, “Exercise Prescriptions for Individuals with AD” in their article outlining appropriate modalities, times, and intensities. 


    We may not yet know enough about the risk factors behind and causes of Alzheimer’s disease, but encouraging a physically active, social lifestyle over the lifespan may prove beneficial. Encourage your clients to eat well, keep moving, and stay engaged socially. And in the gym or studio, consider a well-balanced routine tailored to each client’s abilities, determined both by exercise testing you yourself administer and by input from their medical team and caregivers.

  • ACSM Hot Topic | Recognizing Sudden Cardiac Arrest in Athletes

    by Greg Margason | Jun 21, 2023
    On June 2, Jonathan Drezner, M.D., director of the University of Washington’s Center for Sports Cardiology, delivered the 2023 John R. Sutton Clinical Lecture at ACSM’s annual meeting covering sudden cardiac arrest in athletes. Learn how to recognize and respond to these not uncommon events by viewing the video from Dr. Drezner's lecture below and reviewing an emergency action plan infographic created by ACSM.

    This information is crucial for anyone involved in athletics, from medical professionals to coaches and trainers, parents, and athletes themselves. 

    line with grey, dark blue and light blue sections


    Emergency Action Plan for SCA infographic

    Click to download

  • Active Voice | Caffeine May Increase the Health Benefits of Exercise; Latte da!

    by Greg Margason | Jun 09, 2023
    Caffeine May Increase the Health Benefits of Exercise; Latte da!

    Exercise is good for you. There are many ways by which exercise favorably modifies health. One way is through a chemical known as interleukin-6, usually abbreviated as IL-6. During and following exercise, skeletal muscles release IL-6 into the blood. It is then transported throughout the body where it can have positive effects. For example, the release of IL-6 during and following acute bouts of exercise is thought to contribute to a decrease in the fat that accumulates around the waist.

    The amount of IL-6 released from skeletal muscles during and following exercise appears to be determined by the duration and the intensity of the exercise; generally, more is better. Unfortunately, for a variety reasons, many people are unwilling or unable to participate in long-duration exercise or exercise characterized by sustained high-intensities. These people may be missing out on the IL-6 mediated health benefits associated with exercise.

    Enter caffeine.

    Caffeine is one of the active ingredients in coffee. According to previous research from other laboratories, caffeine increases the amount of IL-6 released into the blood following long-duration and high-intensity exercise. However, almost all of this research was completed by studying males only.

    In our research project, published in the June 2023 issue of Medicine & Science in Sports & Exercise®, we studied both males and females to address the question as to whether caffeine would increase the amount of IL-6 in the blood after 30 minutes of moderate-intensity exercise. That is, we would study the interaction between caffeine and a common workout duration at an intensity that many people would find manageable.

    Ten males and ten females, aged 25 ±7 years, participated in the study. In general, these study participants were habitual exercisers who were considered recreationally active. Most were of average cardiorespiratory fitness for their age. Following initial screening and baseline testing, each of the participants returned to the lab for two experimental visits, separated by at least a week. Each visit began with ingesting either a capsule containing an ingredient that has no physiological effect (a placebo), or caffeine. The caffeine dose was individualized and based on body mass (6 mg of caffeine per kg body mass). For most participants, this would be the equivalent of two to three strong cups of drip coffee. One hour later, each participant rode an exercise cycle for 30-minutes at a moderate intensity (approximately 60% of their maximal aerobic capacity).

    When we looked at all the results together, we found that caffeine increased the amount of IL-6 in the blood after exercise. However, when we separated the results into males and females, we found that caffeine only increased the IL-6 response in the males.

    At this time, we do not know why the males and females responded differently to caffeine and exercise; this question could be addressed in future research. The implication of our current study is that caffeine may increase the IL-6 mediated health benefits of 30 minutes of moderate-intensity exercise in males.

    Kieran Abbotts
    Kieran Abbotts
    obtained his M.S. in health and exercise science from Colorado State University. He is currently a Ph.D. student in the Department of Human Physiology at the University of Oregon. His research focuses on the factors underlying how environmental and physical stressors impact human health and physiology. He is a member of ACSM.

    Christopher Bell
    Christopher Bell, Ph.D.
    , is an associate professor in the Department of Health and Exercise Science at Colorado State University. Together with his graduate students, he addresses a variety of research questions pertaining to human health, physiological function and exercise performance.

    Viewpoints presented in ACSM Bulletin commentaries reflect opinions of the authors and do not necessarily represent positions or policies of ACSM. Active Voice authors who have received financial or other considerations from a commercial entity associated with their topic must disclose such relationships at the time they accept an invitation to write for the ACSM Bulletin.