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2014 | 42 | 1 | 201-213

Article title

Avoiding Systematic Errors in Isometric Squat-Related Studies without Pre-Familiarization by Using Sufficient Numbers of Trials


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There is no scientific evidence in the literature indicating that maximal isometric strength measures can be assessed within 3 trials. We questioned whether the results of isometric squat-related studies in which maximal isometric squat strength (MISS) testing was performed using limited numbers of trials without pre-familiarization might have included systematic errors, especially those resulting from acute learning effects. Forty resistance-trained male participants performed 8 isometric squat trials without pre-familiarization. The highest measures in the first “n” trials (3 ≤ n ≤ 8) of these 8 squats were regarded as MISS obtained using 6 different MISS test methods featuring different numbers of trials (The Best of n Trials Method [BnT]). When B3T and B8T were paired with other methods, high reliability was found between the paired methods in terms of intraclass correlation coefficients (0.93-0.98) and coefficients of variation (3.4-7.0%). The Wilcoxon’s signed rank test indicated that MISS obtained using B3T and B8T were lower (p < 0.001) and higher (p < 0.001), respectively, than those obtained using other methods. The Bland- Altman method revealed a lack of agreement between any of the paired methods. Simulation studies illustrated that increasing the number of trials to 9-10 using a relatively large sample size (i.e., ≥ 24) could be an effective means of obtaining the actual MISS values of the participants. The common use of a limited number of trials in MISS tests without pre-familiarization appears to have no solid scientific base. Our findings suggest that the number of trials should be increased in commonly used MISS tests to avoid learning effect-related systematic errors









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1 - 10 - 2014
10 - 10 - 2014


  • Coaching Education Department, Division of Movement and Training Sciences, School of Physical Education and Sports, Ege University, Bornova, İzmir, TÜRKİYE
  • Division of Movement and Training Sciences, Institute of Health Sciences, Ege University, Bornova, İzmir, TÜRKİYE


  • Abernethy P, Wilson G, Logan P. Strength and power assessment. Issues, controversies and challenges. Sports Med, 1995; 19(6): 401-417[PubMed][Crossref]
  • Alegre LM, Jimenez F, Gonzalo-Orden JM, Martin-Acero R, Aguado X. Effects of dynamic resistance training on fascicle length and isometric strength. J Sports Sci, 2006; 24(5): 501-508[PubMed][Crossref]
  • Atkinson G, Nevill AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med, 1998; 26(4): 217-238[Crossref][PubMed]
  • Balshaw TG, Hunter AM. Evaluation of electromyography normalisation methods for the back squat. J Electromyogr Kines, 2012; 22(2): 308-319[Crossref][WoS]
  • Bland JM, Altman DG. Measuring agreement in method comparison studies. Stat Methods Med Res, 1999; 8(2): 135-160[PubMed][Crossref]
  • Blazevich AW, Cannavan D. Strength Testing. In E. M. Winter (Ed.), Sport and exercise physiology testing guidelines: The British Association of Sport and Exercise Sciences Guide - Volume II: Exercise and clinical testing (1st ed.). New York, NY: Routledge, 130-137; 2006
  • Brown LE, Weir JP. ASEP procedures recommendation I: Accurate assessment of muscular strength and power. J Exerc Physiol, 2001; 4(3): 1-21
  • Cormie P, Deane RS, Triplett NT, McBride JM. Acute effects of whole-body vibration on muscle activity, strength, and power. J Strength Cond Res, 2006; 20(2): 257-261[PubMed]
  • Demura S, Miyaguchi K, Shin S, Uchida Y. Effectiveness of the 1RM estimation method based on isometric squat using a back-dynamometer. J Strength Cond Res, 2010; 24(10): 2742-2748[WoS]
  • Dumke CL, Pfaffenroth CM, McBride JM, McCauley GO. Relationship between muscle strength, power and stiffness and running economy in trained male runners. Int J Sports Physiol Perform, 2010; 5(2): 249-261[PubMed]
  • Gabriel DA, Kamen G, Frost G. Neural adaptations to resistive exercise: mechanisms and recommendations for training practices. Sports Med, 2006; 36(2): 133-149[PubMed][Crossref]
  • Gallagher S, Moore JM, Stobbe TJ. Isometric, Isoinertial, and Psychophysical Strength Testing: Devices and Protocols. In S. Kumar (Ed.), Muscle strength. Boca Raton: CRC Press, 129-156; 2004
  • Gallagher S, Moore JS, Stobbe TJ. Physical strength assessment in ergonomics. Fairfax, Va.: American Industrial Hygiene Association, 1-64; 1998
  • Green LA, Parro JJ, Gabriel DA. Quantifying the familiarization period for maximal resistive exercise. Appl Physiol Nutr Metab, 2014; 39: 1-7[WoS]
  • Herda TJ, Cramer JT, Ryan ED, McHugh MP, Stout JR. Acute effects of static versus dynamic stretching on isometric peak torque, electromyography, and mechanomyography of the biceps femoris muscle. J Strength Cond Res, 2008; 22(3): 809-817[WoS][PubMed][Crossref]
  • Hopkins WG. Measures of reliability in sports medicine and science. Sports Med, 2000; 30(1): 1-15[PubMed][Crossref]
  • Hopkins WG, Schabort EJ, Hawley JA. Reliability of power in physical performance tests. Sports Med, 2001; 31(3): 211-234[Crossref][PubMed]
  • Kline RB. Beyond significance testing: Reforming data analysis methods in behavioral research. Washington, DC American Psychological Association, 58; 2004
  • Krishnan C, Allen EJ, Williams GN. Torque-based triggering improves stimulus timing precision in activation tests. Muscle Nerve, 2009; 40(1): 130-133[Crossref][PubMed][WoS]
  • Kroemer KH. Assessment of human muscle strength for engineering purposes: a review of the basics. Ergonomics, 1999; 42(1): 74-93[PubMed][Crossref]
  • Kunz R, Oxman AD. The unpredictability paradox: review of empirical comparisons of randomised and non-randomised clinical trials. Brit Med J, 1998; 317(7167): 1185-1190[Crossref]
  • Markovic G, Jaric S. Movement performance and body size: the relationship for different groups of tests. Eur J Appl Physiol, 2004; 92(1-2): 139-149[Crossref][PubMed]
  • Markovic G, Jaric S. Is vertical jump height a body size-independent measure of muscle power? J Sport Sci, 2007; 25(12): 1355-1363[WoS][Crossref]
  • McBride JM, Cormie P, Deane R. Isometric squat force output and muscle activity in stable and unstable conditions. J Strength Cond Res, 2006; 20(4): 915-918[PubMed]
  • McBride JM, Deane R, Nimphius S. Effect of stretching on agonist-antagonist muscle activity and muscle force output during single and multiple joint isometric contractions. Scand J Med Sci Sports, 2007; 17(1): 54-60[WoS][PubMed]
  • Morrow JR, Jackson AW. How significant is your reliability. Res Q Exercise Sport, 1993; 64(3): 352-355[Crossref]
  • Newton RU, Hakkinen K, Hakkinen A, McCormick M, Volek J, Kraemer WJ. Mixed-methods resistance training increases power and strength of young and older men. Med Sci Sports Exerc, 2002; 34(8): 1367-1375[Crossref]
  • Nuzzo JL, McBride JM, Cormie P, McCaulley GO. Relationship between countermovement jump performance and multijoint isometric and dynamic tests of strength. J Strength Cond Res, 2008; 22(3): 699-707[PubMed][WoS][Crossref]
  • Rahmani A, Viale F, Dalleau G, Lacour JR. Force/velocity and power/velocity relationships in squat exercise. Eur J Appl Physiol, 2001; 84(3): 227-232[Crossref][PubMed]
  • Tillin NA, Bishop D. Factors modulating post-activation potentiation and its effect on performance of subsequent explosive activities. Sports Med, 2009; 39(2): 147-166[Crossref][WoS][PubMed]
  • Verdera F, Champavier L, Schmidt C, Bermon S, Marconnet P. Reliability and validity of a new device to measure isometric strength in polyarticular exercises. J Sport Med Phys Fit, 1999; 39(2): 113-119
  • Wallerstein LF, Barroso R, Tricoli V, Mello MT, Ugrinowitsch C. The influence of familiarization sessions on the stability of ramp and ballistic isometric torque in older adults. J Aging Phys Act, 2010; 18(4): 390-400[PubMed]
  • Watanabe K, Akima H. Normalized EMG to normalized torque relationship of vastus intermedius muscle during isometric knee extension. Eur J Appl Physiol, 2009; 106(5): 665-673[PubMed][Crossref][WoS]
  • Weir JP. Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. J Strength Cond Res, 2005; 19(1): 231-240[PubMed]
  • Whitley JD,Elliott. Learning component in repetitive maximal static contractions. Percept Motor Skill, 1968; 27: 1195-1200[Crossref]
  • Wilson G. Assessment of muscle function by isometric tests. In V. R. Preedy and T. J. Peters (Eds.), Skeletal muscle: Pathology, diagnosis and management of disease. London: Greenwich Medical Media, 443; 2002

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