This may have convinced me to start doing some active work on hip flexors as a finishing exercise.
That said, all these studies annoy me. With a sample of 13 (untrained) subjects, there are several problems:
1 – SEM is going to be huge. (IE – huge to the extent that even the entire change could be explained by chance)
2 – Untrained – Guys who are starting at a 5.6 40 yard dash time would be folks that would fall below average (I think) and definitely below average in athletic populations
3 – Any protocol will make big gains for these types
Why are there not any studies on strength and speed gains amongst trained subjects? How hard would it be to take 2 largish cohorts and put them through different training protocols for 2-4 months and measure gains?
I’m thinking groups of 50+ athletes and strict adherence to a program.
Obviously that will still only answer the short term question, but that is better than what currently exists which doesn’t really even answer the question of short term performance improvements.
There are a number of reasons that there are not many studies on trained athletes subjects.
First and foremost is access and study design. It may be different overseas, but it is rare for sports coaches or strength coaches to be involved with the PhD’s in Exercise Science/Kinesiology departments that are performing research. Some view themselves as doing two distictly different jobs, PhDs teach and research and coaches coach. Even if they did work together it is difficult to ethically put together well designed training studies with competitive athletes. A quality training study would divide the subject population into three groups; two distinctly different training groups and a control group that doesn’t perform any training. Reseachers and institutional review boards could not ethically ask competitive athletes to not train, so a true control is out. On top of that if you divide subjects into 2 or more training interventions, you as researchers are hypothesizing that certain interventions or training protocols will work better than the others, meaning you may impair performance, which again walks the fine line of being unethical. This is why often times any study with trained athletes is short, so any “negative” effects will wash out when they return to normal training.
Additionally, can you envision any coach saying, “Yeah, take my athletes that I recruited, and who’s performance my job depends on, and train them in a way that might not be optimal, or for that matter any way other than what has worked for me. Sounds good, when do we start.” Highly unlikely.
On a tangent, many training studies lack enough variation to show difference or are not applicable to what you would do with your athlete’s outside of the lab because there is often a “need” to equate total training volume or volume-load. As an example, if a study wanted to compare heavy strength training and plyometrics and their effect on vertical jump. If the lifting protocol was 5 sets x 6 reps = 30 reps, then the plyo group would perform a scheme to get them to 30 depth jumps (e.g. 10 x 3) to get them to 30 reps so we can’t say that one group improved simply because they did more work. But what if as coaches (not researchers) we would not have out athlete’s perform 30 depth jumps, maybe we would only prescribe 15 because we want to minimize fataigue and in turn maximize jump height, or RFD, or their Reactive Strength Index score. Additionally, we rarely train physical qualities in strict isolation, yet most of the time studies are designed to study the isolated effects of one type of training on one quality to limit confounding or Type I or Type II error. It is frustrating because then we can’t see the synergistic effects of different types of training.
I would love to see more case studies of the actual training of elite teams or athletes but many hold on secretively to their methods and training records because sports is big business.
I will say there is/has been some fantastic integrated research coming out of Australia on trained athletes by Warren Young, Daniel Baker, Tim Gabbett, John Cronin, Mike Newton and others. Their studies use high level athletes and assess the actual means and methods these athletes use in their training and they are progressive/advanced in the types of training they use. I would highly recommend that people look into their work.