WEBVTT 00:00:00.000 --> 00:00:02.740 Test what you know. Don't test something unique. 00:00:02.960 --> 00:00:06.339 If the athletes are going to be measured in something 00:00:06.339 --> 00:00:10.220 make sure it's something they do regularly. Hi, 00:00:10.220 --> 00:00:12.099 Marie -Claire. It's my pleasure to have you on 00:00:12.099 --> 00:00:14.179 The Evidence Strong Show for the second time. 00:00:14.279 --> 00:00:16.660 Please briefly introduce yourself for three people 00:00:16.660 --> 00:00:18.500 who haven't seen the first interview. Thanks 00:00:18.500 --> 00:00:20.679 for having me. My name is Marie -Claire Jeannot. 00:00:20.839 --> 00:00:24.359 I typically go by MC in the sports space. And 00:00:24.359 --> 00:00:27.420 I'm currently a postdoctoral researcher at the 00:00:27.420 --> 00:00:30.359 University of Victoria in beautiful British Columbia, 00:00:30.600 --> 00:00:34.759 Canada. And I just finished my PhD on the classification 00:00:34.759 --> 00:00:38.179 of different strength qualities. And I'm also 00:00:38.179 --> 00:00:40.859 a strength and conditioning coach. I work with 00:00:40.859 --> 00:00:43.320 the Canadian Sport Institute here in Canada, 00:00:43.399 --> 00:00:46.179 as well as the Professional Women's Hockey League 00:00:46.179 --> 00:00:48.600 here in Vancouver. All right. So huge experience 00:00:48.600 --> 00:00:51.079 working in strength and conditioning and doing 00:00:51.079 --> 00:00:54.100 research. So I'm super excited to have you and 00:00:54.100 --> 00:00:56.979 pick up your brain specifically on your newest 00:00:56.979 --> 00:01:00.579 study on countermovement jump and back squat. 00:01:00.759 --> 00:01:03.780 So let's start with some kind of definition of 00:01:03.780 --> 00:01:07.120 strength and what we should know about strength 00:01:07.120 --> 00:01:10.200 before we go dive. deep into the study. Yeah, 00:01:10.299 --> 00:01:12.859 that's a great start. And that is actually the 00:01:12.859 --> 00:01:15.379 definition of strength is what led us to doing 00:01:15.379 --> 00:01:18.019 this study altogether, as well as many other 00:01:18.019 --> 00:01:20.859 studies of my PhD. And so for the purpose of 00:01:20.859 --> 00:01:23.859 today and what is kind of currently existing 00:01:23.859 --> 00:01:26.439 in the literature is strength is an expression 00:01:26.439 --> 00:01:29.959 of force on an object or environment. And since 00:01:29.959 --> 00:01:32.640 that's a relatively broad term and can be expressed 00:01:32.640 --> 00:01:34.980 in many different ways, we have different forms 00:01:34.980 --> 00:01:38.269 or different domains or different types of maximal 00:01:38.269 --> 00:01:41.329 strength. Do we want to go quickly into the types 00:01:41.329 --> 00:01:44.109 so then we can align them with what you did in 00:01:44.109 --> 00:01:47.010 your study? Yeah, great. So we can define strength. 00:01:47.049 --> 00:01:48.849 And this is what currently kind of has come from 00:01:48.849 --> 00:01:52.170 my research through my PhD is there are four 00:01:52.170 --> 00:01:54.829 different main types of strength, reactive strength, 00:01:55.209 --> 00:01:57.629 light dynamic strength, heavy dynamic strength, 00:01:57.829 --> 00:02:00.650 and isometric strength. And within those four 00:02:00.650 --> 00:02:03.209 domains, there are subdomains. So for instance, 00:02:03.329 --> 00:02:06.829 within isometric strength, we have early isometric 00:02:06.829 --> 00:02:09.409 strength. and maximal isometric strength. Within 00:02:09.409 --> 00:02:13.289 the dynamic strengths, we have timing, a force, 00:02:13.430 --> 00:02:15.530 and an outcome variable. And within reactive 00:02:15.530 --> 00:02:18.550 strength, we have timing and outcome variables. 00:02:18.810 --> 00:02:21.969 So those subdomains kind of shift depending on 00:02:21.969 --> 00:02:24.490 the population that you're assessing, but that's 00:02:24.490 --> 00:02:26.750 the general rule of thumb as we come from our 00:02:26.750 --> 00:02:30.050 research. So your approach to strength is very 00:02:30.050 --> 00:02:33.810 analytical, but also very, very rooted in practice. 00:02:33.930 --> 00:02:37.199 So we want to get the athletes strong. But we 00:02:37.199 --> 00:02:40.759 also want to test them in a way that doesn't 00:02:40.759 --> 00:02:43.800 make them tired, sore and so on, does not pose 00:02:43.800 --> 00:02:47.539 a risk of injury, but allows us to kind of guess 00:02:47.539 --> 00:02:49.919 that they are getting better, getting stronger 00:02:49.919 --> 00:02:54.800 or not. And from my area, which is Olympic weightlifting, 00:02:55.039 --> 00:02:57.800 we know that both a counter movement jump and 00:02:57.800 --> 00:03:00.300 back squat are correlated with weightlifting 00:03:00.300 --> 00:03:03.759 performance and are often used to test whether 00:03:03.759 --> 00:03:06.639 the athlete is progressing. the case when we 00:03:06.639 --> 00:03:10.219 can't or don't want to test them on Olympic weightlifting 00:03:10.219 --> 00:03:13.719 movements. So that's the broader context. Now, 00:03:13.740 --> 00:03:16.240 why you study? What were you trying to do and 00:03:16.240 --> 00:03:18.319 why? Yeah, I mean, you make some good points 00:03:18.319 --> 00:03:20.780 here. One being that we don't always want to 00:03:20.780 --> 00:03:23.379 devote an entire training session to testing, 00:03:23.479 --> 00:03:26.219 and we don't necessarily want that to be a separate 00:03:26.219 --> 00:03:29.039 entity. And we're kind of leaning towards informing 00:03:29.039 --> 00:03:33.060 practices of monitoring training and different 00:03:33.060 --> 00:03:36.240 tests and different exercises. we can use to 00:03:36.240 --> 00:03:38.759 effectively measure those exercises and use that 00:03:38.759 --> 00:03:41.300 to track progress. And so you make two really 00:03:41.300 --> 00:03:44.419 good examples there of a one rep back squat and 00:03:44.419 --> 00:03:47.960 a countermovement jump as proxy measures or measures 00:03:47.960 --> 00:03:50.080 of different expressions of strength to understand. 00:03:50.539 --> 00:03:52.979 progress and there's a recent trend right now 00:03:52.979 --> 00:03:56.460 kind of in practice that we don't necessarily 00:03:56.460 --> 00:03:59.639 need all of these tests we want to capture the 00:03:59.639 --> 00:04:02.219 range of strength expressions that are available 00:04:02.219 --> 00:04:04.900 but we want to do so in the fewest number of 00:04:04.900 --> 00:04:08.340 tests that we can and tests that we can also 00:04:08.340 --> 00:04:10.580 use for training purposes so if you don't have 00:04:10.580 --> 00:04:13.860 a back squat in your you know a heavy heavy you 00:04:13.860 --> 00:04:16.139 know one or three rep max back squat in your 00:04:16.139 --> 00:04:18.160 program but you have a loaded counter movement 00:04:18.160 --> 00:04:20.980 jump in your program Wouldn't it be nice if we 00:04:20.980 --> 00:04:22.759 can just measure the loaded countermovement jump 00:04:22.759 --> 00:04:24.959 instead of having to do the back squat, but it 00:04:24.959 --> 00:04:27.240 would still measure a maximal quality of strength? 00:04:27.540 --> 00:04:30.079 So those were the practical scenarios that led 00:04:30.079 --> 00:04:33.319 us to this study in particular, as well as some 00:04:33.319 --> 00:04:37.300 nuance around, you know, what if we perform that 00:04:37.300 --> 00:04:39.300 countermovement jump, that loaded countermovement 00:04:39.300 --> 00:04:41.439 jump, sorry, on force plates? Does that tell 00:04:41.439 --> 00:04:44.060 us more information? Can we combine it with metrics 00:04:44.060 --> 00:04:46.620 from an unloaded countermovement jump that we're 00:04:46.620 --> 00:04:49.300 probably doing anyways, or is really low? barrier 00:04:49.300 --> 00:04:52.290 exercise to include in a test battery. collectively 00:04:52.290 --> 00:04:55.170 does that information tell us enough about the 00:04:55.170 --> 00:04:58.089 performance of an athlete that we don't need 00:04:58.089 --> 00:05:00.649 the one rep max bass squad? Or do we need it 00:05:00.649 --> 00:05:02.829 in order to capture that range of strength? Awesome. 00:05:02.910 --> 00:05:05.209 So how did you set up your study? Yeah, so we 00:05:05.209 --> 00:05:08.930 had 19 resistance trained males. And what we 00:05:08.930 --> 00:05:11.389 did for that recruitment process is tried to 00:05:11.389 --> 00:05:15.110 get a nice range of athletes based on their 1RM 00:05:15.110 --> 00:05:16.949 performance. They're all resistance trained, 00:05:17.069 --> 00:05:19.269 but we essentially had a range of participants 00:05:19.269 --> 00:05:21.790 with like 100 kilo bass. squat and those with 00:05:21.790 --> 00:05:24.149 200 kilo back squat. So we had a range that helped 00:05:24.149 --> 00:05:27.149 with our regression models. And what we did was 00:05:27.149 --> 00:05:30.009 a standardized procedure of an unloaded counter 00:05:30.009 --> 00:05:32.670 -ribbon jump and an incrementally loaded counter 00:05:32.670 --> 00:05:35.310 -ribbon jump, starting at 20 % body mass on the 00:05:35.310 --> 00:05:38.230 bar up to 100 % body mass on the bar. And then 00:05:38.230 --> 00:05:41.250 after a nice long rest, they each performed a 00:05:41.250 --> 00:05:44.930 one rep max back squat to a standard depth. And 00:05:44.930 --> 00:05:47.410 so it was cross -sectional in nature. Now, all 00:05:47.410 --> 00:05:49.709 of the jumps were performed on force platforms 00:05:49.709 --> 00:05:51.990 where Whereas the back squat was not. It was 00:05:51.990 --> 00:05:54.910 just performed on a regular setup. And we just 00:05:54.910 --> 00:05:58.970 took the maximal values, the maximal kilos of 00:05:58.970 --> 00:06:01.949 that water. And now in terms of the measurements, 00:06:02.149 --> 00:06:05.750 what did you... Well, obviously, if you use force 00:06:05.750 --> 00:06:08.730 plates, anyone who has tried, you can have, I 00:06:08.730 --> 00:06:12.110 don't know, 200 to 400 measurements taken. Yeah. 00:06:12.680 --> 00:06:17.139 with each jump. So what have you decided to actually 00:06:17.139 --> 00:06:20.160 monitor and analyze? Yeah, no, it's a great question 00:06:20.160 --> 00:06:23.220 and is important in the process of understanding 00:06:23.220 --> 00:06:25.519 this study. So we use previous literature to 00:06:25.519 --> 00:06:27.420 understand that there are probably three main 00:06:27.420 --> 00:06:30.220 factors or types of strength or types of metrics 00:06:30.220 --> 00:06:32.220 that we can use from the counter -movement jump 00:06:32.220 --> 00:06:35.220 without over -analyzing or over -including those 00:06:35.220 --> 00:06:39.220 metrics. And we took an impulse, so an impulse 00:06:39.220 --> 00:06:41.199 from the counter -movement jump, which essentially, 00:06:41.379 --> 00:06:43.579 like propulsive of impulse and it is very closely 00:06:43.579 --> 00:06:45.579 related to jump height. So if someone was to 00:06:45.579 --> 00:06:47.839 use the results from the study, they could probably 00:06:47.839 --> 00:06:49.920 sub in jump height for that particular metric. 00:06:50.180 --> 00:06:53.120 We also took timing. Yes, go ahead. Could we 00:06:53.120 --> 00:06:56.699 just define the impulse? Yes. So it is the force 00:06:56.699 --> 00:06:59.959 produced over time in the concentric or propulsive 00:06:59.959 --> 00:07:02.759 phase of the countermovement. So if you actually 00:07:02.759 --> 00:07:05.660 take the eccentric impulse, it actually cancels 00:07:05.660 --> 00:07:08.259 itself out when you go through the unweighing 00:07:08.259 --> 00:07:10.519 and the braking phase. So if you look at a total 00:07:10.519 --> 00:07:13.240 impulse in a countermovement jump, it actually 00:07:13.240 --> 00:07:16.620 equates to the propulsive aspect of that action. 00:07:16.699 --> 00:07:19.160 So that's the pushing upwards from the braking 00:07:19.160 --> 00:07:22.889 to when you leave the ground. over time that 00:07:22.889 --> 00:07:25.870 you produce in that section of the jump is what 00:07:25.870 --> 00:07:28.029 we measured. And that is directly proportional 00:07:28.029 --> 00:07:31.529 to jump height as a lot of the jump height equations. 00:07:31.649 --> 00:07:33.829 And consider the most appropriate equation used 00:07:33.829 --> 00:07:36.029 to generate jump height from a force plate is 00:07:36.029 --> 00:07:38.230 the impulse momentum method. So it uses that 00:07:38.230 --> 00:07:41.009 impulse to calculate jump height. So they're 00:07:41.009 --> 00:07:43.050 very closely related. Another metric that we 00:07:43.050 --> 00:07:45.930 used was timing of the jumps. We used eccentric 00:07:45.930 --> 00:07:48.569 duration as it was the more, had the most variance 00:07:48.569 --> 00:07:51.350 across participants. And that was used as a time. 00:07:51.399 --> 00:07:54.319 factor of the counter -moving jump. We also used 00:07:54.319 --> 00:07:57.240 force. So some people call it kind of the driver 00:07:57.240 --> 00:07:59.939 aspect of a counter -moving jump, but essentially 00:07:59.939 --> 00:08:03.120 we used net propulsive force as another unique 00:08:03.120 --> 00:08:05.459 factor for the counter -moving jump. So those 00:08:05.459 --> 00:08:08.040 were the three main domains of strength that 00:08:08.040 --> 00:08:10.019 we had Netrix represented from the counter -moving 00:08:10.019 --> 00:08:12.300 jumps that we used in the regression models, 00:08:12.399 --> 00:08:14.680 both in the unloaded and each of the loaded tasks. 00:08:15.079 --> 00:08:17.519 And the kilograms for the back squat. And kilos 00:08:17.519 --> 00:08:20.339 for the back squat, yes. A secondary aim was 00:08:20.339 --> 00:08:23.420 looking... at the intact waveforms. Right. Okay, 00:08:24.180 --> 00:08:26.579 great. So this one is a little bit more complicated, 00:08:26.699 --> 00:08:29.819 but I'm hoping it'll make sense. So a secondary 00:08:29.819 --> 00:08:33.399 aim of this study was to investigate the changes 00:08:33.399 --> 00:08:38.259 in force patterning between the loaded jump conditions. 00:08:38.500 --> 00:08:41.659 So with the practical scenario of, you know, 00:08:41.679 --> 00:08:44.879 if we are faced with a situation where the metrics 00:08:44.879 --> 00:08:49.779 from any of the loaded jumps contribute to the 00:08:49.779 --> 00:08:51.940 same amount of explained variance, you know, 00:08:51.960 --> 00:08:53.799 one rep backs basketball or kind of, you know, 00:08:53.820 --> 00:08:56.799 we consider it to represent a similar expression 00:08:56.799 --> 00:08:59.940 of strength. Therefore, maybe we can choose any 00:08:59.940 --> 00:09:01.879 of the loaded jump conditions that are more suitable 00:09:01.879 --> 00:09:04.620 for our athletes. We wanted to provide the practitioner 00:09:04.620 --> 00:09:07.159 with some information on how different those 00:09:07.159 --> 00:09:11.080 loaded jumps were so that we can start to decide 00:09:11.080 --> 00:09:14.320 which one we want to use for training and end 00:09:14.320 --> 00:09:17.940 testing that best matches our sport or training 00:09:17.940 --> 00:09:21.279 demands. And so one approach to this question 00:09:21.279 --> 00:09:24.320 was to look at the intact waveform. So that is 00:09:24.320 --> 00:09:28.620 the non broken down force time curve, and seeing 00:09:28.620 --> 00:09:30.559 if there are statistical differences between 00:09:30.559 --> 00:09:34.759 the intact the whole jump over time. Now we did 00:09:34.759 --> 00:09:38.299 something called time normalized the the curves. 00:09:38.500 --> 00:09:42.620 So let's say there was a 20 % countermovement 00:09:42.620 --> 00:09:46.559 jump and and then a 40 % body weight countermovement 00:09:46.559 --> 00:09:49.899 jump. If the jump was just slowed down, so that 00:09:49.899 --> 00:09:52.220 is the exact same force patterning everything 00:09:52.220 --> 00:09:54.740 was just a little bit slower which is something 00:09:54.740 --> 00:09:58.039 that we hypothesized, then the curves would look 00:09:58.039 --> 00:10:00.080 exactly the same if they were time normalized. 00:10:00.559 --> 00:10:03.500 What we found though, is that when we did time 00:10:03.500 --> 00:10:06.379 normalize the curves, there were different strategies 00:10:06.379 --> 00:10:09.539 involved with performing that jump. So those 00:10:09.539 --> 00:10:13.899 who, even with the addition of 20 % of body mass, 00:10:14.279 --> 00:10:18.039 there were changes in the way athletes were unloading 00:10:18.039 --> 00:10:19.940 and loading onto the bar in order to jump as 00:10:19.940 --> 00:10:22.899 high as they could. Now we did use non -standardized 00:10:22.899 --> 00:10:25.009 jump depth, which I think in future... research 00:10:25.009 --> 00:10:27.830 it would be beneficial to see if these changes 00:10:27.830 --> 00:10:31.769 did exist with a standardized depth, but we did 00:10:31.769 --> 00:10:34.590 this intentionally to see how people were able 00:10:34.590 --> 00:10:37.669 to, you know, maximally express force in a countermovement 00:10:37.669 --> 00:10:40.330 jump under different loads and how that changes 00:10:40.330 --> 00:10:43.789 their force patterning. So moving backwards to 00:10:43.789 --> 00:10:46.929 the actual analysis that we did, we took the 00:10:46.929 --> 00:10:49.509 intact waveforms, we normalized them so they 00:10:49.509 --> 00:10:52.710 all lasted in a total of one second. And then 00:10:52.710 --> 00:10:55.269 we ran the curves through something called a 00:10:55.269 --> 00:10:58.190 statistical parametric mapping. And it is essentially 00:10:58.190 --> 00:11:00.940 a statistical... approach that looks for differences 00:11:00.940 --> 00:11:04.740 in the absolute force production at each instance 00:11:04.740 --> 00:11:08.360 along the curve. So if it's one second, that's 00:11:08.360 --> 00:11:11.299 1 ,000 indices. It looked at every one of those 00:11:11.299 --> 00:11:14.519 1 ,000 indices and looked for a statistical difference 00:11:14.519 --> 00:11:17.080 between the different conditions. And in that 00:11:17.080 --> 00:11:19.320 analysis, we noticed that there were specific 00:11:19.320 --> 00:11:22.019 trends, particularly around tow -off, so the 00:11:22.019 --> 00:11:24.960 takeoff portion of the jump, that was most impacted 00:11:24.960 --> 00:11:27.720 by an increase in load. So when you look at the... 00:11:28.240 --> 00:11:30.720 actual curves, you can see some dark red kind 00:11:30.720 --> 00:11:32.820 of in the ANOVA that was run. And that is an 00:11:32.820 --> 00:11:35.480 indication that there were significant differences 00:11:35.480 --> 00:11:39.259 in the absolute force at the end time of that 00:11:39.259 --> 00:11:41.860 curve. One of our main outcomes of this particular 00:11:41.860 --> 00:11:44.659 portion of the study was that each curve was 00:11:44.659 --> 00:11:47.000 different. And there were actually some weird 00:11:47.000 --> 00:11:49.779 changes that happened around the heavier loads. 00:11:49.840 --> 00:11:53.220 So between the 80 % and the 100 % body mass condition, 00:11:53.480 --> 00:11:55.899 we found that strategy was changed quite a bit 00:11:55.899 --> 00:11:59.610 in a sense where maybe the athletes that we had 00:11:59.610 --> 00:12:02.769 in the study weren't super accustomed to maximally 00:12:02.769 --> 00:12:05.330 expressing force under the condition of 100 % 00:12:05.330 --> 00:12:08.409 body mass jump. So that led us to some understanding 00:12:08.409 --> 00:12:11.149 of, okay, the athletes have to know how to perform 00:12:11.149 --> 00:12:13.850 the task quite well in order for us to use it 00:12:13.850 --> 00:12:16.809 as a performance measure. Just while listening, 00:12:17.090 --> 00:12:19.990 what did it mean that the athletes adjust their 00:12:19.990 --> 00:12:23.090 strategy and how they perform can the movement 00:12:23.090 --> 00:12:26.070 jump right at the end? So everything at the beginning 00:12:26.070 --> 00:12:29.289 that... The dip, let's say, go ahead, is pretty 00:12:29.289 --> 00:12:32.889 similar. And then where they're supposed to go 00:12:32.889 --> 00:12:36.470 up, that's where everything changes. At the beginning, 00:12:36.590 --> 00:12:39.330 so with the small loading of weight, that seemed 00:12:39.330 --> 00:12:42.409 to be the most impacted section was at the toe 00:12:42.409 --> 00:12:44.509 off. But as a little bit more weight was added, 00:12:44.710 --> 00:12:48.769 the breaking portion was also greatly affected. 00:12:49.029 --> 00:12:52.610 And that wasn't super surprising because the 00:12:52.610 --> 00:12:55.529 extra load of that weight in the breaking and 00:12:55.529 --> 00:12:58.200 the... rate of force and total force that you 00:12:58.200 --> 00:13:00.700 have to develop in that segment should theoretically 00:13:00.700 --> 00:13:02.639 change unless you are really, really, really 00:13:02.639 --> 00:13:06.200 strong in that position. But interestingly, yeah, 00:13:06.299 --> 00:13:09.279 the toe -off was a little bit more affected by 00:13:09.279 --> 00:13:12.100 smaller amounts than the eccentric loading in 00:13:12.100 --> 00:13:14.340 this population. Right. What else? What else 00:13:14.340 --> 00:13:16.840 have you found? So with the regression models, 00:13:17.019 --> 00:13:19.799 so we took those three metrics from each of the 00:13:19.799 --> 00:13:23.080 counter movement jumps and to understand the 00:13:23.080 --> 00:13:25.000 shared variance essentially between the load. 00:13:25.100 --> 00:13:27.259 counter -moving jumps and the one rep max, we 00:13:27.259 --> 00:13:29.519 used multiple regression models. And what we 00:13:29.519 --> 00:13:34.200 found were, first of all, both timing and force. 00:13:34.779 --> 00:13:36.759 So timing and force in the countermovement had 00:13:36.759 --> 00:13:41.259 very, very little influence on one rep max performance, 00:13:41.580 --> 00:13:44.720 meaning that those who are good at each of those 00:13:44.720 --> 00:13:47.000 aspects of the countermovement were not necessarily 00:13:47.000 --> 00:13:51.480 good at one rep maxes. But the impulse, so as 00:13:51.480 --> 00:13:54.440 I mentioned earlier, the impulse is greatly associated 00:13:54.440 --> 00:13:57.519 with jump height. So that actually had a strong 00:13:57.519 --> 00:14:00.899 correlation to one rep max backspin and contributed 00:14:00.899 --> 00:14:04.100 most to the regression models. And we found that... 00:14:04.110 --> 00:14:06.690 there was a range from about 30 % shared variance 00:14:06.690 --> 00:14:10.830 to 66 % shared variance. So in the 80 % body 00:14:10.830 --> 00:14:13.750 mass countermovement jump that the jump height 00:14:13.750 --> 00:14:16.850 or the impulse measured from that condition explained 00:14:16.850 --> 00:14:20.470 up to 66 % of variance in the one round ex -bass 00:14:20.470 --> 00:14:23.049 squat. So that leaves a good chunk of variance 00:14:23.049 --> 00:14:25.870 that's unexplained. And so that kind of led us 00:14:25.870 --> 00:14:28.730 to the conclusion that, yeah, okay, there is 00:14:28.730 --> 00:14:32.070 definitely some similarity here, but we can't 00:14:32.070 --> 00:14:34.700 fully replace the... one rep max back squat if 00:14:34.700 --> 00:14:38.480 that particular strength characteristics is important 00:14:38.480 --> 00:14:41.379 to you we cannot fully replace it just by using 00:14:41.379 --> 00:14:43.620 metrics from the loaded countermovement jump 00:14:43.620 --> 00:14:46.659 we also found that combining both an unloaded 00:14:46.659 --> 00:14:49.279 countermovement jump impulse and an impulse from 00:14:49.279 --> 00:14:51.700 another loaded countermovement jump did not improve 00:14:51.700 --> 00:14:54.019 the model performance at all and the reason we 00:14:54.019 --> 00:14:56.700 did this was you're likely going to do an unloaded 00:14:56.700 --> 00:14:59.200 countermovement jump anyways in a strength assessment 00:14:59.200 --> 00:15:01.360 because it's super accessible most people can 00:15:01.360 --> 00:15:03.639 do it it's almost included in warmup, so why 00:15:03.639 --> 00:15:05.700 not include it in our models to see if it helps 00:15:05.700 --> 00:15:09.039 the performance? It did not. So overall, we found 00:15:09.039 --> 00:15:11.500 that the loaded counter movement jumps were pretty 00:15:11.500 --> 00:15:14.720 similar to the unloaded. So you could kind of 00:15:14.720 --> 00:15:17.879 pick and choose what you wanted there. Whereas 00:15:17.879 --> 00:15:20.679 the one rep max back squat was a pretty unique 00:15:20.679 --> 00:15:24.519 factor. And so overall, we suggest that you choose 00:15:24.519 --> 00:15:27.240 either an unloaded counter movement or a loaded 00:15:27.240 --> 00:15:29.360 counter movement if it's more specific to your 00:15:29.360 --> 00:15:32.139 sport and a one rep max back squat in order to 00:15:32.139 --> 00:15:34.700 capture the range of information available from. 00:15:35.440 --> 00:15:38.779 the dynamic tasks from that range from unloaded 00:15:38.779 --> 00:15:41.639 countermovement jump to a maximal dynamic load, 00:15:41.759 --> 00:15:43.500 which we would consider to be a one rep max. 00:15:43.799 --> 00:15:46.100 All right. I may have missed it. The heaviest 00:15:46.100 --> 00:15:49.639 countermovement jump were the most similar to 00:15:49.639 --> 00:15:52.240 back squat, but still not enough to replace it. 00:15:52.379 --> 00:15:54.899 Oh yeah. This is actually a good point. We actually 00:15:54.899 --> 00:15:56.860 found that the, so we did countermovement jumps 00:15:56.860 --> 00:16:00.500 up to 100 % body mass, but we found that the 00:16:00.500 --> 00:16:03.799 100 % body mass condition actually had lower 00:16:03.799 --> 00:16:07.240 relation. or lower shared variance to when we're 00:16:07.240 --> 00:16:10.340 at max back performance than the 80 % condition. 00:16:10.639 --> 00:16:13.779 And we hypothesized or tried to explain that 00:16:13.779 --> 00:16:16.600 as, you know, we don't think that the athletes 00:16:16.600 --> 00:16:18.679 included in this study were super comfortable 00:16:18.679 --> 00:16:22.539 with the 100 % body weight condition. And that 00:16:22.539 --> 00:16:26.299 could have led to maximal expression of force 00:16:26.299 --> 00:16:29.059 not to be optimized in that condition. So they 00:16:29.059 --> 00:16:31.639 weren't super accustomed to it. And so performing 00:16:31.639 --> 00:16:34.450 that task didn't necessarily allow that. to have 00:16:34.450 --> 00:16:36.409 a maximal expression of force. It was more just 00:16:36.409 --> 00:16:38.710 figuring out how to do the movement and move 00:16:38.710 --> 00:16:41.769 under that load. And so that lends to our larger 00:16:41.769 --> 00:16:44.509 discussions when we're selecting one test over 00:16:44.509 --> 00:16:47.309 the other, which is make sure that your athletes 00:16:47.309 --> 00:16:49.909 or your participants or whatnot know how to perform 00:16:49.909 --> 00:16:53.610 the task prior to using it for monitoring or 00:16:53.610 --> 00:16:56.970 testing purposes. It also lends us more to the 00:16:56.970 --> 00:17:00.779 discussion around selecting a task that you would 00:17:00.779 --> 00:17:02.919 do anyways in the weight room or as part of your 00:17:02.919 --> 00:17:05.339 training, because chances are the athlete knows 00:17:05.339 --> 00:17:09.000 how to perform that over some unique tasks that 00:17:09.000 --> 00:17:11.880 you only use for monitoring or testing purposes. 00:17:12.200 --> 00:17:14.279 So overall, that was one of the major conclusions 00:17:14.279 --> 00:17:16.740 as well. You know, something that came from our 00:17:16.740 --> 00:17:19.819 research is that it's almost not sports specific, 00:17:19.980 --> 00:17:22.740 a lot of these things, but who your strength 00:17:22.740 --> 00:17:24.740 and conditioning coach is, what kind of tests 00:17:24.740 --> 00:17:28.099 and what kind of exercises you do with your strength 00:17:28.099 --> 00:17:30.190 and conditioning coach might be more. more indicative 00:17:30.190 --> 00:17:32.930 of how well you're trained for different exercises, 00:17:33.089 --> 00:17:35.410 not necessarily your sport. With that said, though, 00:17:35.470 --> 00:17:38.049 there are, you know, specific trends. You wouldn't 00:17:38.049 --> 00:17:41.009 necessarily have a super heavy countermovement 00:17:41.009 --> 00:17:44.269 jump in sports that don't involve moving other 00:17:44.269 --> 00:17:47.269 mass, you know? So yeah, it would be sports specific. 00:17:47.410 --> 00:17:51.329 And I think these results can still help decisions 00:17:51.329 --> 00:17:54.230 in those cohorts where it is maybe only up to 00:17:54.230 --> 00:17:57.430 50 % body. mass that you're doing a loaded counter 00:17:57.430 --> 00:17:59.930 -driven jump, but you prefer doing that over 00:17:59.930 --> 00:18:02.390 a one rep max back squat, you now know that you 00:18:02.390 --> 00:18:05.910 can adequately predict or predict up to 60 % 00:18:05.910 --> 00:18:08.589 of that variance using a slightly lighter load. 00:18:08.750 --> 00:18:10.450 You don't necessarily need to go all the way 00:18:10.450 --> 00:18:13.789 up to 100 % or the benefit of going from 40 % 00:18:13.789 --> 00:18:17.490 to 80 % is only 3 % or whatever it is of more 00:18:17.490 --> 00:18:20.029 explained variance. So you can maybe make better 00:18:20.029 --> 00:18:22.049 decisions around there as well. Right, right. 00:18:22.170 --> 00:18:24.690 That's very useful because you can consider safety. 00:18:25.069 --> 00:18:28.130 specificity to your athlete day, training age, 00:18:28.349 --> 00:18:30.410 what you're normally doing, you know, all these 00:18:30.410 --> 00:18:33.329 factors you can factor in while you're making 00:18:33.329 --> 00:18:35.869 decisions on training. Yeah, exactly. And that's 00:18:35.869 --> 00:18:37.650 what we wanted to do with this paper and our 00:18:37.650 --> 00:18:39.930 other papers is not say that, you know, this 00:18:39.930 --> 00:18:42.210 weight is better than the other, but rather provide 00:18:42.210 --> 00:18:44.769 the information of, you know, when you are selecting 00:18:44.769 --> 00:18:47.750 this load based off of the laundry list of other 00:18:47.750 --> 00:18:49.509 factors that you're making this decision off 00:18:49.509 --> 00:18:51.650 of, this is what you're compromising, or this 00:18:51.650 --> 00:18:54.190 is, you know, one of the factors in the equation. 00:18:54.279 --> 00:18:57.480 and it helps us just make better decisions in 00:18:57.480 --> 00:19:00.720 the training environment and in testing environment. 00:19:00.940 --> 00:19:03.500 Right. Okay. Could we then bring it all together 00:19:03.500 --> 00:19:07.450 and produce some kind of takeaways for... the 00:19:07.450 --> 00:19:09.849 coaches on how to use the data from a study. 00:19:09.970 --> 00:19:12.809 Yeah. So overall, I think we wanted to help coaches 00:19:12.809 --> 00:19:15.309 decide how many different strength tests and 00:19:15.309 --> 00:19:17.170 different strength metrics they needed for the 00:19:17.170 --> 00:19:19.710 range of an unloaded countermovement all the 00:19:19.710 --> 00:19:22.789 way up to a one rep max back squat. And what 00:19:22.789 --> 00:19:26.410 we showed in this study is that the three main 00:19:26.410 --> 00:19:28.750 metrics from a countermovement jump, so that 00:19:28.750 --> 00:19:31.869 being a timing, an outcome, and a force metric 00:19:31.869 --> 00:19:34.609 need to be measured through a counter -movement 00:19:34.609 --> 00:19:37.730 jump variant and a one rep max back squat is 00:19:37.730 --> 00:19:40.730 needed in order to count for the range. We can't 00:19:40.730 --> 00:19:44.670 necessarily miss one or two of those in order 00:19:44.670 --> 00:19:46.990 to count for the whole range. Additionally, we 00:19:46.990 --> 00:19:49.849 might not need a loaded counter -movement jump. 00:19:50.029 --> 00:19:51.970 The combination of an unloaded counter -movement 00:19:51.970 --> 00:19:54.309 jump and one rep max back squat does a pretty 00:19:54.309 --> 00:19:56.690 good job of collecting the range, at least in 00:19:56.690 --> 00:19:58.970 recreational individuals, and further research 00:19:58.970 --> 00:20:01.259 is needed to explore. or whether that's the case 00:20:01.259 --> 00:20:04.599 in more trained individuals. Awesome. And usually 00:20:04.599 --> 00:20:07.880 I finish with two short questions. And today 00:20:07.880 --> 00:20:11.519 I will ask you to, maybe you are an expert in 00:20:11.519 --> 00:20:14.400 strength. So what is one nugget of knowledge 00:20:14.400 --> 00:20:16.420 you want all the coaches to know about strength? 00:20:16.660 --> 00:20:18.960 The biggest thing I would say, and I'm going 00:20:18.960 --> 00:20:21.920 to lean on the strength testing side, is test 00:20:21.920 --> 00:20:25.099 what you know. Don't test something unique. If 00:20:25.099 --> 00:20:28.180 the athletes are going to be measured in something, 00:20:28.299 --> 00:20:29.740 make sure it's something they do right. regularly. 00:20:29.960 --> 00:20:32.400 Awesome. And last question is where people can 00:20:32.400 --> 00:20:36.039 find you online if they want to keep up with 00:20:36.039 --> 00:20:39.259 your research or ask a question. Yeah. ResearchGate 00:20:39.259 --> 00:20:42.140 is a great place for most of my research and 00:20:42.140 --> 00:20:45.460 Google Scholar. And I've boycotted the Twitter 00:20:45.460 --> 00:20:48.019 space. So I'm more on Instagram these days. And 00:20:48.019 --> 00:20:50.140 that's where I'll post some papers and post some 00:20:50.140 --> 00:20:52.400 summaries of research coming out. Thank you so 00:20:52.400 --> 00:20:56.019 much, MC. A pleasure as usual. All the best for 00:20:56.019 --> 00:20:59.039 all the next projects. Thank you very much. Thanks 00:20:59.039 --> 00:20:59.500 for having me on