Achilles Tendon Stiffness of Division I Track and Field Athletes

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31 Comments on “Achilles Tendon Stiffness of Division I Track and Field Athletes

  1. JORDYN BROEK (19 hours ago): Great project and poster! You mentioned that there is increased stiffness in males who experienced a previous injury. Are you aware of what types of injuries resulted in this – and do you think there is a correlation there? Why do you think there was not a correlation between increased stiffness in females who experienced a previous injury as there was for males?
    Thanks

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    • Hi Jordyn! One of our research limitations is that we did not go into detail about our participant’s previous injuries. It was more of a ‘yes’ or ‘no’ type of question. For example, we asked if they have had a previous injury from the waist down in their lifetime. Our participants would state what type of injury, where, and when, but we did not include that specific data into our research, just a ‘yes’ or ‘no.’ This is because we weren’t consistent with asking about their injuries and the participants could not recall their injury in the level of specificity we would need. I don’t recall there being an injury more prominent than another, so we did not find a correlation between a specific injury type. I am unsure why there wasn’t a significant finding with increased stiffness in females who have experienced an injury. This could possibly be due to the type of injury, rehabilitation program, or baseline level of tendon stiffness (males have increased stiffness in comparison to women.) Thank you for your question!

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  2. KYLEIGH MORAN (2 days ago): Great job on your project, this is a very interesting topic! You mentioned that a couple of your limitations include unequal male to female ratio and timing of measurement. What influence do you think having an equal male to female ratio would have on your overall results? What was the timing of measurements and why was this considered a limitation?

    Thank you!

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    • Hi Kyleigh, thank you for your question! Having an equal male to female ratio may have given us a better understanding of the differences in tendon stiffness between males and females, along with possibly observing more significant findings within the biological sex. This could have also given us an idea of factors within or between the biological sexes that may or may not contribute to tendon stiffness. Our research group took measurements at the beginning of the season. We hypothesized we may see some possible changes in these measurements if multiple measurements would be taken throughout the season and at the end of the season. These changes could be due to increased activity levels, specific sport training, stress, etc. Hope this answers your questions!

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      • Sorry, I did not see that you had already replied to this question, Jess!

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    • Hey Kyleigh, thanks for your question! We had very few males compared to female athletes so our mean AT stiffness shown on the table for the poster could change, and be more applicable/accurate, if we had an even amount of males compared to females due to their stiffness typically reading higher. The time of measurements could be considered because the measurements were taken early in the year; mainly being done in August and September (A bulk of the measurements were taken the week of their first organized practice week). Most of the athletes would be coming off of their summer training which is likely different than their in-season training. We also had a lot of freshman student athletes coming off of their summer training; this can lead to the question of how much could their tendon stiffness change later in the season with college training vs high school training. Same for the rest of the T&F athletes; could their AT stiffness be higher in-season rather than prior to the start of both fall and spring seasons? I hope this helps!

      – Syd

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  3. ABBY RIPPERDA (2 days ago): Great job! I was a participant in the study and am currently doing further research with tendon stiffness. In our research it has generally been accepted that increased tendon stiffness is advantageous as allows for more more energy to be released quickly and therefore more force to be released. Therefore my question for you is: why do you think that the male athletes with a history of injury had a higher average tendon stiffness as opposed to those without a history of injury and do you think that the stiffness may have been a contributing factor to their injury?

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    • Hey Abby! We questioned the same thing when we saw these results. Some of our male athletes who presented with higher AT stiffness were typically shorter in height. Height and AT stiffness demonstrated a negative correlation with a significant p-value. We discussed that there would need to be more individuals with varying heights to see if this would have changed our results and given us more information. Many of our male athletes were relatively close in height. We also could have done a better job of understanding their injury, how long ago it was, and what they did post injury in relation to rehabilitation. After injury there can be a lot of focus on rehabilitating the injured limb over bilateral training and the patient turns out to be even stronger after rehab on the previously injured limb compared to the non-injured limb. More research with a larger pool of athletes would be ideal to see if this correlation would change or become stronger. I hope this kind of helps!
      – Syd

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  4. TIEGEN LINDNER (3 days ago): Very neat! While analyzing this research, I notice that the researchers found increased mean stiffness in male injury compared to male non-injury groups. This was very interesting to me, thinking that past injury would have “broken” that tendon down to a deeper degree. How can you account for this finding? Perhaps, those who injure a tendon spend more purposeful time/effort working to improve the abilities of that tendon passed the original “starting” point (regarding stiffness)? Based on your results looking specifically at gender, stiffness, injury risk, and sport performance, what do you believe to be an “ideal” body form keeping in mind both performance and tendon health?

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    • Tiegen, the injury thing definitely surprised us some too. I think one thing to keep in mind is that we have a small sample size for the males, which when you divide them into an injury and non-injury groups, gets even smaller and can skew the data. Also, we classified injury to anything in the lower extremity, not strictly to the Achilles and ankle or foot. In fact looking back, only one of the male athletes had a direct injury to the tendon, which was reoccurring tendinopathy over the past few years. One possibility for the increases stiffness is that these participants compensated for the injury a certain way and their Achilles tendon adapted as needed. As for your other question, I don’t believe there is an “ideal” body form for performance and tendon health. It really is going to depend on so many things including what that person is trying to accomplish and what their goals are. However, I would say it could be an interesting to dig further into for future research.

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  5. BAILEY NEISES (4 days ago): Hey guys,
    I noticed that timing of measurement collection was listed as one of the limitations of your study. Could you possibly expand on that and describe the timing that the measurements were taken for all the participants? I did a little research and found that achilles tendon stiffness increased an average of 18% when measured after a training session in a study completed by Werkhausen et al. This showed me that achilles tendon stiffness can be variable throughout certain activities. Do you guys think that taking consistent measurements after training, during training, or possibly before training could affect the results your study found? Also, if you were to measure it consistently, what time do you think would be the most beneficial?

    Werkhausen, A., Albracht, K., Cronin, N. J., Paulsen, G., Bojsen-Møller, J., & Seynnes, O. R. (2018). Effect of training-induced changes in Achilles tendon stiffness on muscle–tendon behavior during landing. Frontiers in Physiology, 9. https://doi.org/10.3389/fph… [trunkated by RED]

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    • Great questions Bailey. All of our measurements for the athletes took place from 8/18-9/16. For most of the power based athletes this meant they were either in their offseason or pre-season. However, for the more endurance athletes, specifically the ones that also participated in cross country too, their measurements took place either right before their season or a few weeks in. I looked at the study you linked and it is interesting to see how much the participants increased their stiffness over 10 weeks of training. 18% seems like a huge jump over that period of time. I think taking consistent measurements would definitely have an impact on our results. When it comes to training, you would obviously want to be increasing stiffness if we assume stiffness has positive effects on injury prevention and performance so tracking it throughout would be another good way to track progress and to see if your programming is working. Another thing I think would be interesting is to measure stiffness periodically throughout an athlete’s season to see how it changes and to look at how they perform and injury prevalence.

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  6. MADDISON HAJEK (5 days ago): Hi all!

    Great work on your research study and creating this poster. I liked that you included a ‘clinical relevance’ in order to concisely describe how this topic and your research results matter to practicing clinicians. Since we are out in rotations right now and my mind is very clinically oriented, my question is based on the literature and your research findings, what would you recommend to a physical therapist right now in regard to tendon stiffness and maximizing physical performance? In other words, would you suggest measuring tendon stiffness as part of the evaluation? If so, what numbers should the clinician be looking for and how will that influence the plan of care?

    Thank you!

    SYDNEY GUSTAF reply (4 days ago): Hey Maddison! Thanks for your question. This is something we kind of talked a lot about as a group; right now we are unsure what an “optimal” AT stiffness is, in regards to performance, in an athletic population. You may consider utilizing a MyotonPRO during an evaluation with someone suffering from a Achilles or LE injury by comparing the AT stiffness from one side to the other. For example, if the R LE was injured or presents with weakness or pain you may check the L AT and compare the results from side to side and how the stiffness is impacted as progress is made throughout rehab. In other words, you may be able to use this as an asterisk’s sign throughout your rehabilitation plan. I hope this makes sense!

    – Syd

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  7. AUSTIN BROWN (5 days ago): Hello everyone; great job with your research!
    The stated limitations of this study suggested that further research is warranted to develop a deeper and valid understanding as to what factors correlate with Achilles tendon stiffness among Division 1 track and field athletes. This study was conducted at The University of South Dakota (USD), which in comparison to a more juggernaut program in track and field such as The University of Oregon, USD is a much smaller program. If you conducted this study again but had a different pool of eligible participants—such as Oregon T&F athletes
    —would you be inclined to think that the data from their program would better support your purpose of this study?

    JESSICA THUM reply (4 days ago): Hi Austin! I anticipate there would be more significant findings in a larger population such as the Oregon T&F athletes. It would be helpful to have a more even distribution of males and females, a greater variety of the type of T&F athletes (throwers, sprinters, distance, jumpers, etc), and greater cultural diversity. Having more diversity and a larger population to collect data from would allow researchers more insight into the differences in stiffness (males vs females, sprinter vs distance, thrower vs jumper, etc) and possible contributors to those differences. Sample size was a limitation for our study and was a barrier for us in finding more significant results. Thank you for your question!

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  8. HALEY FRITZA (5 days ago): Hello everyone,
    Great job on this research, this topic was especially interesting to me! My question would be, considering that there was a negative correlation between height and stiffness in males and also previously injured males, could the same be true for female athletes? If not, why do you think that is and what factors between male and female do you think are significant in influencing this?

    ERIN LUKEN reply (4 days ago): Thank you for your questions. We did not find a negative correlation between height and stiffness of females in our research, as we did with males. There are so many factors that may have contributed to that finding. Some that come to mind are flexibility, overall lifestyle, smaller difference in height between female subjects, similar body weight between female subjects, and oral contraceptive use. Although it was not included on our research poster, we did look at the impact oral contraceptives have on tendon stiffness. Previous research has found that those with history of long-term use of oral contraceptives have decreased tendon stiffness in comparison to those with short-term use. Our research found a similar result; decreased stiffness with use of oral contraceptives, although we did not take length of oral contraceptive use into consideration. It is important to keep in mind our small sample size with these results. Thanks again for your question, hopefully this response answered it!

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  9. JORDYN BERNSTEIN (6 days ago): Hello Erin, Sydney, Jess, Jason, and Drew,
    First of all nice job, your poster is very visually appealing and I like the way all your data is displayed! Obviously this cross sectional study was looking only at track and field athletes. I am wondering if you have any hypothesizes as to what the results would be if you looked at another population that maybe is not as physical active. Additionally, do you have any speculations as to what potentially caused the reduced tendon stiffness in females when compared to males? Ideally, how would you like to see physical therapists using this information in practice?

    ERIN LUKEN reply (4 days ago): Hi Jordyn!
    Thank you for your questions. I would hypothesize that the results from a “less” physically active group would be different from the results found in our study. I personally believe that the “less” active population would have increased stiffness simply due to their inactive lifestyle, leading to increased BMI, decreased muscle mass, and decreased flexibility. Previous research has found that higher BMI is correlated with increased AT stiffness. Considering BMI doesn’t take muscle mass into account, one may question: does “unhealthy” weight impact tendon stiffness differently than muscle weight? There are so many different factors that are yet to be discovered and analyzed, as we have mentioned on our poster. We were originally going to collect data on USD psychology graduate students so we would have a control group to compare our data to. Hopefully more research is to come in terms of this topic! I kind of talked about your second question in response to Haley’s question. Possibly flexibility, overall lifestyle, smaller differences in height and weight between female subjects, and oral contraceptive use may be the cause of decreased AT stiffness in females. We have found that those who take oral contraceptives have decreased AT stiffness. Lastly, our results do not provide very much clinical relevance at this point. Ideally, we would reach a point in research where clinicians could recommend AT stretches or strengthening based on the patient’s presenting factors in order to increase performance and/or reduce injury risk.

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    • Great job on the poster! I saw Bailey, kind of mention this but, were these measurements taken during the offseason or during the athletes in-season? Another interesting aspect that could be further assessed would be the athletes hydration and their Achilles Tendon stiffness. Overall, good job.

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      • Nick, all the measurements were taken 8/18-9/16 for the athletes. For some this was the pre-season, while others, mainly the endurance athletes who also participated in cross country, we measured right before their season or a few weeks into the season. I think hydration levels would be a great thing to look at in relation to the tendon stiffness. Our group had talked about all the different directions you could go in the future, but I don’t recall hydration ever being brought up. Considering how important hydration is to performance and injury prevention it would definitely be something interesting to look at.

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  10. Hi group! Great work on your poster. I enjoyed the neatness, graphics, and overall presentation of information. One question I had as I was reading through was what sparked your research idea in the first place? Also, are Achilles injuries known to be common in track and field athletes and how did you decide on utilizing this population rather than other athletes such as basketball or tennis players for example?

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    • Hi Lexi – thank you for your questions! Our research topic was chosen by Dr. Dewald and was something each of us sparked interest in when deciding what topic of research we wanted to pursue. I would not say that track and field athletes are more likely to have Achilles injuries than other athletes but are common injuries for many athletes. Dr. Dewald has a relationship with these athletes at the University of South Dakota, so with an already established relationship, it was easier to collect data for our research. I do think it would be very interesting and beneficial to see how different athletes compare in regards to tendon stiffness and injury. Hopefully that answered your questions!

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  11. Great job on your poster! This topic is very interesting and pertinent to our profession as achilles tendon injuries are very prevalent. It was mentioned that females taking birth control were included in your demographic data but nothing was mentioned regarding the purpose of doing so. According to the article written by Ham et al, all muscles and tendons show significantly greater stiffness during menstruation than ovulation after actively being contracted. My question is: Do you think women on their cycle skewed the results as compared to those not on their cycle at the time of the measurement? Thanks!

    Ham, Seoungho et al. “Greater Muscle Stiffness during Contraction at Menstruation as Measured by Shear-Wave Elastography.” The Tohoku journal of experimental medicine vol. 250,4 (2020): 207-213. doi:10.1620/tjem.250.207

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    • Hi Ali! Thank you for your question. Data surrounding menstrual cycles and tendon stiffness hasn’t been consistent according to the research articles we have found. However, there is a decent amount of data suggesting those on their menstrual cycle experience laxity in their ligaments, such as with the ACL. Because of the data we found specifically with oral contraceptive use and decreased tendon stiffness, I believe that women being on their menstrual cycle could have skewed the results. We did not ask our participants about their cycle/if they are on it, but it would be a good idea for future research! The influence of hormones on bodily tissues, such as tendons and ligaments, is seeming to become more popular.

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  12. Hi guys! Great job on your poster, I found your research very interesting. I saw that in your methods section you collected information on if females were taking oral contraceptives, but I didn’t see if that played a role in the tendon stiffness. Would you expand on if you saw any correlation between oral contraceptive use and tendon stiffness? If you didn’t do anything with that information, what would you expect to see?

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    • Hello Allie! That is a valid question as oral contraceptive use and its possible effects on tendon stiffness was an area of interest that we were very excited to see data on. I can tell you that with the athletes we did have, the data showed significantly lower AT stiffness in females currently using oral contraceptives (664 N/m), compared to females who were not (702 N/m). The issue with documenting that in our actual results came from the fact that we did not feel our information gathering from our subjects was adequate enough. We simply asked if they were using oral contraceptives, with no follow up questions. We realized it would be important to know specific kinds of oral contraceptives, how long they have been taking them, and to also not exclude hormonal and non-hormonal intrauterine devices (IUDs). Due to the complexities that arose from gathering this data and the lack of context with the question form at intake, we decided to leave this data out of our final report. Very interesting topic for future research for sure!

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  13. Hello group, excellent presentation and poster! I like that the layout is simple but effective and not too distracting to the reader. I did have a few questions though. First, you found no significant difference in tendon stiffness in female power athletes and female endurance athletes. Is this consistent with what you found when reviewing the available literature prior to starting this project? If so, why do you think that is? (My thought process: I would think that there would be differences in tendon stiffness for a power athlete who needs to produce an extreme amount of force quickly one time vs an endurance athlete that needs to maintain low-level exertion for extended periods of time.) If not, is that one of the inconsistencies in the literature that you were referring to in your “conclusion” section, and why do you think that your findings were inconsistent with the findings in other studies?

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    • Hey Spencer. Great question! You are spot on with your intuition about foreseen differences in achilles tendon stiffness in regard to specific sport specialization. While the research we found was somewhat controversial, the majority of published work demonstrated trends towards power athletes having increased AT stiffness when compared to endurance athletes. The thought process would be that power athletes would have a stiffer AT in order to have an extremely fast and strong burst of energy for a very short duration of time, while an endurance runner may have less stiffness in order to sustain a running pace, with much lower load, for a greater amount of time. It is important to note that while endurance runners would be expected to demonstrate decreased stiffness, lower values do not necessarily mean more efficiency. This is just an analysis of averages within a group so the higher level endurance runners could still demonstrate increased stiffness in comparison to their competitors. In regard to our data, the most likely reason we did not see these expected differences most likely comes down to sample size. We did begin to see very slight trends towards increased stiffness in female power athletes compared to endurance athletes, but it was not statistically significant. While I can’t say with absolute confidence, intuition and past research makes us believe this difference could become significant if we continued this research with more subjects. Another possible reason for this non-significant difference can possibly be attributed to the athletes training experience and schedules. We took our measurements at the beginning of the school year when athletes were just arriving to campus and reporting for practice. This means they were not in-season and it is tough to know what type of training each athlete was participating in during the off-season. Some of our subjects were freshman as well, meaning they may not have been exposed to enough of the sport-specific training to yet demonstrate a measurable difference in AT stiffness. Hope this novel of a response answers your question!

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  14. Great project! My question is how you would expect the stiffness to change with different life demands of different ages outside the ages of 18-24 and how would you expect an injury to affect stiffness in ages outside of 18-24.

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    • Hey Tonner, thanks for your question! A few studies we had read talked about how tendons change based on our age, activity level, BMI, etc. After looking at those studies, we hypothesize that stiffness would likely decrease as we age (after our mid-twenties or early thirties) and as our activity level decreases. But there could also be outliers to that hypothesis, such as those who are a lot more active in their 30s than they were in their 20s possibly due to occupational demands (desk job vs heavy labor) and exercise regimen changes (running vs power lifting vs CrossFit vs plyometric training, etc.). We could also include the changes in hormones in both males and females and how this changes as we age. We did find a significant difference in female athletes who took oral contraceptives averaged a lower AT stiffness compared to those who did not; not shown on our poster. Further research needs to be done on how different hormones could impact our AT stiffness. It would be very interesting to follow these athletes over-time and see how their AT stiffness changes as they age. We didn’t really talk much as a group about how AT stiffness would be different for those under the age of 18. In my opinion, I think their AT stiffness could change a lot more (up and down throughout growth) depending on growth spurts and how fast these spurts occur. We know that our bones grow first and our tendons and muscles have to catch up. It would be interesting to study that population more but with less tendon issues occurring in pediatrics and adolescents, it may not be a super helpful study. I hope this helps!

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  15. Hello everyone. First off, the layout of the poster and the information you decided to share with us looks great. My question for you all is in regards to the specific events each athlete was participating in. I am curious if you found any significant differences in tendon stiffness for event specific athletes? For example, does a high jumper, who requires a very quick burst, consistently demonstrate a stiffer tendon when compared to a distance runner? I would be curious to see if there was a relationship within genders for specific events. Also, some food for thought, if you could go back and add anything to include into your research, what do you believe would have been the most beneficial?

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  16. Good job guys, this was very interesting information! I do have one question, was the achilles tendon stiffness measurement taken before or after working out? Do you think that measurements would change if they were taken both before and after working out?

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    • Hi Alex! These measurements were taken during the day between classes or right before the athletes were going to practice. Taking measurements before and after a work out is something we questioned if there would be changes in stiffness, along with before and after a season or training program, etc. Definitely an idea for future research. Thank you for your question!

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