Dissertation ideas

Yea I realised that after writing the post! I havn’t read the original research paper but I will try and find it and find out why 0.098 wasn’t thought to be significant :confused:

Depends on the level of significance they were looking at etc. It’s where or not the improvement is seen to be by chance or as a direct result of the intervention.

On the same lines of what you are thinking about. Look at the links below.

http://www.athleticscoaching.ca/UserFiles/File/Sport%20Science/Theory%20&%20Methodology/Strength/Strength/Schmidtbleicher%20Short%20Term%20Increase%20of%20Explosive%20Strength%20Through%20Max%20Arbitrary%20Contrac.pdf

There is a superior translation in NSA the journal published by IAAF,

http://194.213.2.7/wps/portal/iaaf

It’s interesting to note that the subjects in the study were high class athletes at national and internation standard.

OR why not look at muscle stiffness and compliance on sprint performance?

OR look at the different strength qualities of the phases of the 100m-200m sprints?

cleveland brown’s strength coach tom myslinski wrote a great dissertation on the development of the russian conjugate method, its on elitefts.com

do you know of any other work Tom has been involved with besides Q&A on elite and that one podcast? Does he have an e-mail or contact info?

I handed in my diss on Thursday…

The acute effects of heavy back-squats on maximal velocity sprinting.

ABSTRACT

Recent studies have reported improvements in sprint accelerations when preceded by heavy-back squats (HBS). These improvements have been attributed to postactivation potentiation (PAP). The purpose of the present study was to investigate the effects of the HBS on maximum velocity sprinting. The study consisted of a cross-over design with an experimental condition and a control condition. 10 sprinters and horizontal jumpers participated. In the first testing session, half of the participants performed the control condition, half the experimental. This protocol was repeated during the second testing session but with the two halves exchanging conditions. Prior to testing both conditions completed a standardised 35 minute, sprint specific warm-up including aerobic activity, dynamic flexibility, sprint specific drills and sprints. The testing procedure involved an initial flying-20m sprint, followed 10minutes later by a second flying-20m sprint. At 5 minutes into this 10 minute rest interval the experimental group completed a 3 Repetition Maximum (3RM) HBS, and the control group cycled for 1 minute. When preceded by the HBS, subjects ran 1.13% faster during the flying-20m sprint, although this improvement was not statistically significant. However, participants ran significantly faster (P<0.05) post-HBS than post-cycle. When comparing flying-20m sprint times of the strongest and weakest participants no differences were found. The data from the study suggests that following a thorough sprint warm-up, the HBS potentiates subsequent maximum velocity sprint speed. The significant difference between the post-HBS sprint and post-cycle sprint indicate that the HBS elicits PAP which subsequently augments maximum velocity sprint speed. However, the predominant musculature used in the HBS differs from that used in maximum velocity sprinting, suggesting that improvements were not induced by increases in the contractile properties of the muscles. It is more likely that the HBS potentiated elastic properties of the leg musculature resulting in stiffer ground contacts.

I know the term is not universally agreed on but ‘stiffness’ was the term used in the literature concerned.

Interestingly, in literature I saw Francis (1997) referenced twice explaining Ben johnson had warmed-up with squats… although Charlie denies this I thought???

The CharlieFrancis.com community was mentioned in my acknowledgements…

Congratulations on completing your dissertation! Very interesting conclusions. By the way stiffness is the correct term used in many other fields when talking about elastic response.

My EMS angle on the subject of your dissertation, is that there are potentiation programs in the more serious machines: they are intense bursts at different frequencies to activate different fiber types. I guess they act using the same physiologic mechanism.

On a side-note. My conclusion that performance benefits were related to increased stiffness is supported by literature in the full text…

If anyone is interested Hodgson has a great review of PAP

The response of muscle to volitional or electrically induced stimuli is affected by its contractile history. Fatigue is the most obvious effect of contractile history reflected by the inability of a muscle to generate an expected level of force. However, fatigue can coexist with post-activation potentiation (PAP), which serves to improve muscular performance, especially in endurance exercise and activities involving speed and power. The measured response of muscular performance following some form of contractile activity is the net balance between processes that cause fatigue and the simultaneous processes that result in potentiation. Optimal performance occurs when fatigue has subsided but the potentiated effect still exists. PAP has been demonstrated using electrically induced twitch contractions and attributed to phosphorylation of myosin regulatory light chains, which makes actin and myosin more sensitive to Ca(2+). The potentiated state has also been attributed to an increase in alpha-motoneuron excitability as reflected by changes in the H-reflex. However, the significance of PAP to functional performance has not been well established. A number of recent studies have applied the principles of PAP to short-term motor performance as well as using it as a rationale for producing long-term neuromuscular changes through complex training. Complex training is a training strategy that involves the execution of a heavy resistance exercise (HRE) prior to performing an explosive movement with similar biomechanical characteristics, referred to as a complex pair. The complex pair is then repeated for a number of sets and postulated that over time will produce long-term changes in the ability of a muscle to generate power. The results of these studies are equivocal at this time and, in fact, no training studies have actually been undertaken. The discrepancies among the results of the various studies is due in part to differences in methodology and design, with particular reference to the mode and intensity of the HRE, the length of the rest interval within and between the complex pairs, the type of explosive activity, the training history of the participants, and the nature of the dependent variables. In addition, few of the applied studies have actually included measures of twitch response or H-reflex to determine if the muscles of interest are potentiated. There is clearly more research required in order to clarify the functional significance of PAP and, in particular, the efficacy of complex training in producing long-term neuromuscular adaptations.

Do you think this is similar be the EMS potentiation program found in Globus and Compex electrical muscle stimulators? (Potentiation in Compex, and Endurance Prep or Sprint Prep in Globus). Where can I find Hodgson’s review?

I haven’t used EMS so I can’t really say, but my guess is EMS would increase force through increased calcium released and possible changes in pennation angle of the muscle fibers. This would be similar to PAP however PAP also “primes” the nervous system. Someone with experience using EMS could probably help you on this topic.

In regards to Hodgson’s review use pubmed and search “Hodgson PAP” it is the fourth article down the list. The first article is pretty good as well

Hey Bubka,
Thanks for the article reference: I will read it and report if I find something more. I dug some more in a scientific textbook* at my local University though, which I cite:

PAP goes also under the name of posttetanic potentiation. The book says it can be elicited by either voluntary contractions or electrical simulation. The increase in dorsiflexor twitch force increases from 5% up to 180%, depending on on the electrical stimulation modality.

It is greatest after contractions that last 5s to 10s and decrease with longer-duration contractions. In both voluntary and electrically stimulated (EMS) contractions the process may involve modification of Calcium kinetics, but there is no mention of pennation change. The potentiation effect seems greatest for the twitch (up to 200%), but much less for sustained muscle contractions (10-20%). This happens for both EMS and voluntary contractions.

Note*:
Enoka R. Neuromechanics of human movement. 4th ed. Champaign IL [u.a.]: Human Kinetics; 2008.