Hit Count Volume and Upper Extremity Performance Measures in Division I Volleyball Players Over a Competitive Season
Dustin Javers, SPT, Allison Thielsen, SPT, Hans Tvedt, SPT, and James Whitcher, SPT
(Click on image to expand)
Dustin Javers, SPT, Allison Thielsen, SPT, Hans Tvedt, SPT, and James Whitcher, SPT
(Click on image to expand)
USD PT Research 
Hey guys,
I’ll start things off. I was wondering if you could elaborate further on two things from your study- 1 is just further clarification and the other is the real question.
1) Could you elaborate more on which parameters returned to baseline after the season compared to which parameters did not return to pre-season baseline (I tried as much as I could to blow up the chart but I was unable to read Table 2 clearly). Based on this, my question is:
2) Why do you believe that certain parameters returned to baseline while others did not? Do you believe that given more time post-season these parameters would return to baseline, or do you believe that these would persist as a functional change to the athletes biomechanics indefinitely? Why or why not do you believe this?
Thanks!
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Jordan,
That is a great question. I will first further elaborate on your first question. After measuring the athletes when the season was complete, we actually did not have any parameters that returned back to baseline. Almost all of the parameters showed a trend of returning back towards baseline following the post-season test date, but never fully returned back to baseline. To answer your second question, I do think that if we would have waited or re-tested the same parameters a month later, I believe that we would have seen most, if not all, parameters return very close or even back to baseline measurements. I believe this would have occurred mainly do to the data we collected and the trend this data displayed from week 14 to week 22. In just those short 7-8 weeks, measurements of pain, ROM and strength had already decreased and this was again demonstrated on our last testing date. I believe that our body adapts to changes in motion and strength based on our daily activities. When an athlete is constantly pushing their shoulder ROM to end-range and consistently performing similar overhead activity, these areas (strength and ROM) with be greatly enhanced. I can not say for sure whether these biomechanics are indefinitely changed since that is not what our study analyzed. But, I tend to think of it like any other muscle in our body. When we stretch a muscle each day to end-range, multiple times a day for a month, we would hope to see that muscle lengthen. Now, if we would stop stretching that muscle completely for a month, more than likely that muscle length will regress. My clinical judgement says that the longer the period of time these muscles are stretched out, the longer it will take for them to return back to where they started. I would say that if the muscles were not torn or injured, that strength and ROM would eventually return back to baseline following a long rest period.
I hope this answers your questions!
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Were you able to look into the volleyball team’s strength and conditioning programs to compare preseason to in-season? I just wondered if the strengthening and stretching programs during the season could have had an impact on your variables in addition to hit count.
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Anna,
That is a great question. We did not communicate with the strength and conditioning coach on what exactly the girls were doing for a strength and conditioning program. We mentioned in our limitations that any activities outside of volleyball, whether that be lifting, exercising, playing volleyball outside of practice or games or participating in other sports related activities, were things that we could not control and could potentially impact the results of our study. I would agree that opening up this communication with the strength and conditioning coaches would help us further to analyze and understand other factors that can have an impact on our variables tested.
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Interesting study! I see from Anna’s question and your previous answer that you were not in contact or following the strength and conditioning program your participant’s were likely completing during the season. Based on your research findings, are there any general exercises you would recommend to the strength and conditioning coach in order to decrease risk of injury/pain throughout the season? Or any that you would not recommend the players perform?
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Liz,
Great question! At this juncture we haven’t made any such recommendations or concluded such results. However, it would appropriate to perform exercises that are considered advantageous adaptations such as strength. It would also be appropriate to address losses that occur throughout the season such as internal rotation ROM. Those would be issues that should be addressed.
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Great poster! One question I had while looking over this was whether all of your subjects played the same position or not. Did you make it a point to only recruit outside hitters for your study, or was it whoever wanted to participate? I would imagine it would be important to track the number of spikes that an outside hitter would have vs sets or roll shots from other players. Also, did you account for serves in your hit counts?
Thanks!
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Macie,
We did not limit our study to just hitters, the study was open to anyone who volunteered and met the inclusion criteria. We counted hits as anything that was overhead and the shoulder/arm was forcefully projected forward, which includes strikes such as spikes and serves. Serves were actually a major part of our hit count! Thanks for asking.
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Hey guys,
One question that I had while reading your poster was why you only choose to count hits during practice sessions, and not include hits that occurred during games?
Thanks,
Emily Mensen
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Hi Emily, we choose to count hits during practice because it was a little more consistent compared to games. Although we did not coordinate with coaches on the structure of practice, there was more opportunity for all of our participants to get a greater volume of hits through various drills, as opposed to games, where some players may receive more playing time and the games could go 3 sets or 5 sets. It was also more convenient for us researchers to record hits from recorded practice videos, where we could adjust the speed of the videos as needed and watch the videos on our own schedule. We recorded hits from 2 consecutive practices at 3 different times throughout the season which was more consistent than having to rely on the team’s game schedule. Thanks for the question!
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The poster looks and great and interesting study! I was just wondering if you could elaborate on a couple of questions I had…
1.) I thought it was a good idea to show perceived hit count of the 2 coaches and athlete compared to actual hit count. The question is what was the research looking to gain with that or hope to use that information for because most of the time they were quite different from coach to athlete and actual, which was interesting to me. Some weeks actual was more than perceived and others it was lower. Or I guess if that is even anything worth exploring more??
2.) How come only five volleyball players were observed?
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Hi Allison! To answer your questions,
1) We measured actual vs perceived hit count out of curiosity to see how accurate or aware the players and coaches were of the hit volume during practice. If we had found a correlation to a number of hits with shoulder injury, then we could determine if the coaches or players were aware of their hit volume or how it could be better monitored better to reflect true hit count. The fluctuations in actual and perceived could be based on the length of practice, which drills were performed, how the athletes were feeling that day, etc.
2) We were only able to use the data from 5 athletes because this study was completely voluntary, some athletes did not meet the inclusion criteria, and other athletes were lost due to non-shoulder injuries. That is just how research goes sometimes! Thanks for the question!
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What an interesting study! I just had a few questions while reading through your research as some of the data was difficult to read due the small print. I was curious what the pain relationships were like. Were the athletes that exhibited increased ER ROM and decreased ER strength throughout the season the athletes that were reporting pain? I also was curious if you all took set count into consideration, rather than strictly hit count, as setting or any overhead movement may contribute to the overuse injuries as well. Overall, I found this is to be a great read and I’m interested to hear back form you. Thanks!
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Amazing question. I was hoping someone would comment on the readability of the graphs.
By and large, the ER strength didn’t decrease per say. However, the IR strength did increase over the competitive season. The IR/ER strength ratio changed. Initially it was about 1:1. However, in the offseason the ratio was measured to be 1: 0.7. This is a commonly observed phenomenon in the overhead throwing athlete.
It’s very astute of you to ask about the correlation between ER ROM and Pain. There was a moderate effect size between the ER ROM increase and pain experienced. Meaning that not all, but most, of those who had increases in ER experienced levels of pain.
Great question about the set vs hit differences. You are probably aware of the the differences in these movements. However, one the subjects in this study was the setter for the study. She had very few hits/spikes/etc, but we monitored her variables. She actually didn’t have the changes in IR/ER strength ratios, increase in ER ROM etc. I think if we would have left this subject out, our data would have showed greater changes in the shoulder.
Thanks for the question,
James
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Some of the data is difficult to see, but overall very interesting poster! I have just a few questions for you all. (1) Did you guys see a specific number or range of hits in which pain/loss of ROM could potentially be predicted? From my understanding you guys are stating there could be, I’m just not sure if the specific numbers are in your data. I realize many factors can influence this, but would be interesting to see with “x” number of hits someone was more likely to have a change and further implement tools to help combat that likelihood like you guys stated. (2) As the season progressed, were there any other compensations or effects noted that you were not expecting in regards to the data collected/observations? Thanks!
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