• 14 OCT 14
    • 0
    Best practice

    Best practice

    As a member of BASES looking to gain accreditation as a Chartered Scientist in Sports and Exercise Science I am obliged to follow the code of conduct which is formed around World Medical Association guidelines for conducting scientific experimentation on human volunteers and subjects enrolled into novel investigation for the purposes of scientific progression. Even though a recreational or elite athlete are not subjected to a similar degree of risk benefit as that of a patient with an acute or chronic condition randomised to some intervention or other, nether-the-less the safety and well-being of subjects must be a priority for the practitioner at all times. This applies even if interventions are elective (i.e. prescriptive training or assessments requested by a client). These global regulatory requirements are set out as per the International Conference on Harmonisation (ICH) at the Declaration of Helsinki 1964, after a series of disastrous and ethical experimentation took place on exploited populations. Now, clinicians and manufacturers appraising the medical benefit of pharmaceuticals, surgical interventions and medical devices must seek ethical clearance and follow stringent procedures to avoid undue risks to their subjects. In sport science, the tolerance for clinical surveillance is much lower due to the nature of the exercise intervention or testing of an ergogenic aid, which is mostly non-invasive techniques or are well-research and established supplements like caffeine, electrolytes, proteins and other inert substances with negligible toxicity profiles.

    Having said that, this does not mean that the conditions for conducting a sports science study should be any less stringent than a therapeutic study, as to maximise the quality of the data (avoiding erroneous conduct and measurements) to capture what should either be no difference or significant difference according to difference between treatment groups. Studies performed for the purposes of sports science have been notoriously known to be prone to selection bias due to the difficulty of recruiting enough subjects for a certain inclusion/exclusion criteria, with poor generalisability of studies to real-world scenarios, as these are frequently conducted in heterogenously poorly trained individuals or in elite athletes where results may not be pertinent. In either case, study samples are therefore quite small, meaning it is difficult to power a study to have enough confidence in the results that a difference between groups is not due to random chance. Hundred of subjects are usually required in each treatment group to see small percentage changes, depending on the event rate or continuous outcome being measured in the control group. This ultimately means that protocols should follow best practices of an ordered performance framework to avoid spurious results.

    It is largely the duty of affiliated members of BASES, including ‘closed-loop’ practitioners like myself to make sure they remain ‘in-tune’ with standard approaches to implementing strength and endurance training and physiological assessments and stay abreast of contemporary research in their specialist areas…for me that is cycling performance, muscle biochemistry and metabolism. For that reason practitioners should refer clients with issues outside of their specialist field, such as medicine or physiotherapy to other professionals representing such a discipline.Ensuring the highest standards of safety and working practices as well as a clients well-being is every members paramount concern.

    It is for this reason I remain impartial and as objective as possible to applying solutions and training prescription with known effectiveness to every unique situation. For instance, the discrepancies that exist between the milieu of recommendations and suggestions for measuring training effect by a plethora of ‘professional’ coaches and ‘sports scientists’ are rife. The recent proprietary success of Training Peaks, as an everyday analytical performance platform has substantial benefits. Namely the performance chart manager to visually analyse training volume from both  heart-rate and power data is very helpful, Golden Cheetah have also derived a similar tool from Bannisters TRIMP model. However both a based on quantitating training stresses on mathematically fabricated parameters, FTP and CP which are used to derive TSS and BikeScore. Both FTP (see here) and CP (see here) even though they provide some utility in certain situations, are known to be poor performance indicators which are not well associated (but well correlated, i.e. they follow a similar trend) with actual lactate threshold values of the same athlete.  Even amongst published research, determinations of lactate threshold have evolved over the years, with confusion between terminology and actual physiological events clouding the benefit to athletes. LT1 and LT2, considered to be aerobic and anaerobic turning points, consistent with deflections in heart-rate and blood lactate concentration, as described by Conconi et al. More recently the introduction of the terms lactate turning points have helped to re-define actual physiological events which take place. LT1 or the aerobic threshold is now considered the Lactate Threshold, the point at which blood lactate first rises. LT2 or the anaerobic threshold is now defined as OBLA or the Onset of Blood Lactate Accumulation, the point at which increasing work-rate results in shifting the steady-state balance between lactate production, distribution, metabolism and clearance to one of uncontrolled build-up. As some well studied athletes know, the point just before this is considered the Maximal Lactate Steady State (MLSS) which is the intensity which can be maintained at steady state (without a breaching more than 1mmol/L difference throughout). The MLSS is usually confirmed through a series of 10minute trials to establish the power at which steady-state is achieved. Faude et al explain the concepts of lactate threshold very well indeed. Full review here.

    That means that as a sub-maximal assessment, best practice dictate that it should be conducted alone, separate from any form of VO2max testing, and as an incremental graded ramp protocol achieving ‘volitional exhaustion’ or as close as one can get for determining the peak lactate reading for that particular protocol. Then not only a clearance value can be acquired subsequent to the effort, but more importantly the profile can be modelled using industry standard software, NOT just ‘picking’ the timepoint that is thought to be close to the actual lactate threshold power (MLSS). This is the real difference between best practice and unordered practice, as the practitioner is able to conserve accuracy and reproducibility as long they follow a standard modelling technique, in my case, D-max and intercept tangent methods to give a very robust means of determining small let crucial differences in values pre and post training. Unfortunately many practitioners use inferior techniques to save time, including a redundant approach for standardising wattage at the 4mmol/L point. Although reproducible, this does not provide sufficient opportunity to capture the true threshold which can be either well above and well below 4mmol/L in most individuals. For instance after an effective training period lactate concentrations will change (reduce) for a particular power, although the new threshold may be at a higher lactate concentration (and lower heart rate) meaning an accurately reflective improvement in power is not detectable, or only a smaller change is observed.

    I am sure over time the value of properly conducted lactate profiling will become more apparent to the cycling community, and I believe that ways to measure it will evolve and the scientific definitions will be even clearer. I currently include 4 assessments as part of a 12 month periodisation programme to provide objective evaluation of response and bio-feedback at scheduled periods. This provides necessary insight into how successful a training programme is, and whether revisions are necessary to adapt the schedule to fit the individual athlete more closely, so that the chance of hitting pre-defined objectives is maximised.

     

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