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Heart Rate Deflection

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[[File:HeartRateSimplified.png|right|thumb|500px|A simplified chart of heart rate against exercise intensity showing [[Maximum Heart Rate]], [[Heart Rate Reserve]], [[Resting Heart Rate]] and [[Heart Rate Deflection]].]]
The heart rate deflection point is a controversial way of establishing an athlete's anaerobic threshold[[Lactate Threshold]] (LT), sometimes called the Anaerobic Threshold (AT). The anaerobic threshold Lactate Threshold is where the body starts to rely more on producing energy anaerobically (literally without oxygen) rather than aerobically (literally without with oxygen). The best way of measuring the anaerobic threshold Lactate Threshold is to take a MLSS test, but this requires the analysis of blood sample and have it analyzedsamples. This is obviously invasive, inconvenient, painful and somewhat expensive. In 1980, Italian sport scientist and medical doctor Francesco Conconi developed a test procedure for establishing an athlete anaerobic threshold Lactate Threshold based on heart rate. The idea behind the test is to have the athlete exercise of gradually increasing intensity while recording their heart rate. When the athlete starts to produce energy anaerobically, their heart rate will not go up proportionate to the intensity. This change from linear relationship between heart rate and intensity is called the [[Heart Rate]] Deflection (HR<sub>d</sub>).  
=The Conconi Test=
This The Conconi test should be was described in a 1982 paper<ref name="Conconi-1982"/> and refined in 1996<ref name="Conconi-1996"/>. The original test is performed on a 400 m track with a [[Heart Rate Monitor]] heart rate monitor that will record the test. After a thorough warm-up, the athlete should run at a comfortable pace for 200m, and then increase their pace slightly at each subsequent 200 m. Is the time to cover each 200 m segment needs to be recorded, and this can be done by hitting the lap button on the [[Heart Rate Monitor]]heart rate monitor. The original Conconi test called for the athlete to increase their pace by 0.5 Km/hr, which is remarkably tricky. A modified test has the athlete increasing the pace by 2 seconds per 200 m interval. The test continues until the athlete can no longer runs of the required pace.The 1996 test changed the protocol to increase the pace in a more uniform rather than using steps, and changed to time rather than distance, with increases every 30 seconds.
=Validity of the Conconi test=
The Conconi test is remarkably controversial, with many potential issues<ref name="conconiCook2011"/>.
* There is relatively little scientific support that actually validates the blood lactate levels in comparison to the HR<sub>d</sub>. Conconi's original work compared blood lactate levels at speeds above and below those seen as HR<sub>d</sub>, but the comparisons were performed on separate occasions.
* It is difficult for runners to increase their pace by precise amount and then hold that pace for a given distance.
* The changes in heart rate between each segment may be quite small.
* In many instances the HR<sub>d</sub> is difficult to identify or completely absent.
* Some studies have observed the when the HR<sub>d</sub> is discernible it can occur well above anaerobic threshold, creating a risk of [[Overtraining]]overtraining.* At higher intensities, HR may not reach a steady state, making the deflection hard to detect.
* Other studies have shown a disassociation between HR<sub>d</sub> and the anaerobic threshold.
These concerns and issues make the usefulness of the Conconi test unclear. Personally I would suggest that it is better to either use training paces based on race performance ([[Jack Daniels Running Formula]]), or actually measure blood lactate directly.
 =Directly measuring lactateMeasuring Lactate Threshold=It is possible to measure the lactate level in the blood using a device similar to a blood glucose meter<ref name="Tanner-2010"/>. Just like a blood glucose meter, a small drop of blood must be drawn and applied to a disposable test strip. This process is rather tricky when exercising at high intensity, and stopping to draw blood will obviously interfere with the exercise level. Lactate meters cost $300-500, with this test strips costing around $2/each. There are three Lactate meters on the market, Lactate Pro, Lactate Scout, and Lactate Plus. A review<ref name="LactateMeters"/> indicated that the Lactate Pro and Lactate Plus had good reliability and accuracy, and the Lactate Scout was "relatively good", but not as good as the other two.   =See Also=* [[Resting Heart Rate]]* [[Heart Rate Reserve]]* [[Pulse Oximeter]]* [[Maximum Heart Rate]] 
=References=
<references>
<ref name="conconiCook2011"> I Cook, Was the Conconi test validated by sporting success, expert opinion or good science?, South African Journal for Research in Sport, Physical Education and Recreation, volume 33, issue 1, 2011, ISSN [http://www.ajolworldcat.org/issn/0379-9069 0379-9069], doi [http://dx.doi.org/10.info4314/indexsajrs.phpv33i1.65483 10.4314/sajrs.v33i1.65483]</ref><ref name="Conconi-1982">F. Conconi, M. Ferrari, PG. Ziglio, P. Droghetti, L. Codeca, Determination of the anaerobic threshold by a noninvasive field test in runners., J Appl Physiol Respir Environ Exerc Physiol, volume 52, issue 4, pages 869-73, Apr 1982, PMID [http://www.ncbi.nlm.nih.gov/pubmed/7085420 7085420]</ref><ref name="Conconi-1996">F. Conconi, G. Grazzi, I. Casoni, C. Guglielmini, C. Borsetto, E. Ballarin, G. Mazzoni, M. Patracchini, F. Manfredini, The Conconi test: methodology after 12 years of application., Int J Sports Med, volume 17, issue 7, pages 509-19, Oct 1996, doi [http://dx.doi.org/10.1055/s-2007-972887 10.1055/articles-2007-972887], PMID [http:/view/65483 www.ncbi.nlm.nih.gov/pubmed/8912066 8912066]</ref><ref name="LactateMetersTanner-2010">RK. Tanner, KL. Fuller, ML. Ross, Evaluation of three portable blood lactat..lactate analysers: Lactate Pro, Lactate Scout and Lactate Plus. [, Eur J Appl Physiol, volume 109, issue 3, pages 551-9, Jun 2010, doi [http://dx.doi.org/10. 2010] 1007/s00421-010-1379-9 10.1007/s00421-010- PubMed 1379- NCBI 9], PMID [http://www.ncbi.nlm.nih.gov/pubmed/20145946 20145946]</ref>
</references>

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