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Title: Analysis of reliability and validity of critical power testing in the field
Author: Karsten, Bettina
ISNI:       0000 0004 5354 161X
Awarding Body: University of Greenwich
Current Institution: University of Greenwich
Date of Award: 2014
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Critical Power (CP) provides a useful indicator of training status in continuous activities lasting between approximately 2 and 30 minutes. To date, determination of CP has been mostly constrained to the laboratory. The conventional laboratory protocol commonly requires multi-day time-to-exhaustion tests. The thesis below addresses whether CP can a) be determined without multi-day exhaustive trials and b) be determined in the field. Studies compared the findings of conventional laboratory determination methods with novel protocols in which either the testing mode, the recovery period between exhaustive trials, or the environment were manipulated. Study 1 demonstrates that the recently developed 3-min all-out protocol does not result in valid CP values, when using the isokinetic ergometer mode. Results indicated low levels of agreement (mean of 23-45 W) between conventionally determined CP and values derived through the 3-min all-out protocol. The average prediction error associated with the relationship between CP and the 3-min all-out End Power was 7%. In Study 2, values of CP derived through a conventional laboratory CP protocol were compared with those determined outdoors on a cycling track. High levels of agreement (mean of 2 -14 W) were observed between the laboratory and field values of CP. The average prediction error associated with the relationship between laboratory and field CP was 2.2%. Based in the laboratory, Study 3 compares a 24 h recovery protocol with a 3 h and a 30 min recovery protocols. High levels of agreement (mean of -2 - 11 W and -2 - 8 W respectively) were observed across protocols. The average prediction error associated with the relationship between the 24 h and 3 h and the 24 h and 30 min protocols was 2.4% and 3.3% respectively, suggesting that determination of CP could be made more ‘athlete-friendly’ by shortening the conventional 3-day protocol to one day. Study 4 uses three protocols to evaluate the shortened 30 min protocol in ecological valid open road conditions. Values of CP derived from laboratory protocols were compared to a) those derived from pre-planned and ‘grouped’ maximal efforts of 3 min, 7 min and 12 min with a 30 min recovery period between efforts (protocol 1), b) those of discrete and randomly performed, yet still pre-planned maximal efforts of the same durations (protocol 2), and c) to those extracted from self-directed training and racing of these same durations (protocol 3). The average prediction error associated with the relationship between the laboratory and the field values of CP was 3.1% (protocol 1), 4.9% (protocol 2) and 4.1% (protocol 3). Results, whilst providing high levels of agreement, also suggested that in particular protocols 1 and 3 potentially provide a practical and arguably ecologically valid alternative to the conventional laboratory protocol. Study 5 further investigates the overall CP determination procedure by comparing collected values of CP derived through 3 data points with both, CP laboratory and field values derived through 2 data points. High levels of agreement and low prediction errors (average 3.2%) associated with the relationship between 3 data points and 2 data points-derived CP were observed. Studies collectively provide support for the acceptance of field performance testing using CP, with either a 30 min inter-maximal effort recovery period or alternatively the extraction of non-planned specified maximal efforts from training and racing data. Overall the investigations described in the thesis suggest that CP determination is feasible beyond the laboratory and that consumer-level technology provides satisfactory ease and reliability of measurement in this context. Moreover, these novel CP determination methods allow coaches to continuously monitor their athletes.
Supervisor: Beedie, Christopher ; Jobson, Simon ; Hopker, James Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QP Physiology ; RC1200 Sports Medicine