PMID- 28002178
OWN - NLM
STAT- MEDLINE
DCOM- 20180604
LR  - 20180604
IS  - 1533-4287 (Electronic)
IS  - 1064-8011 (Linking)
VI  - 31
IP  - 12
DP  - 2017 Dec
TI  - Effect of Different Onset Thresholds on Isometric Midthigh Pull Force-Time 
      Variables.
PG  - 3463-3473
LID - 10.1519/JSC.0000000000001765 [doi]
AB  - Dos'Santos, T, Jones, PA, Comfort, P, and Thomas, C. Effect of different onset 
      thresholds on isometric midthigh pull force-time variables. J Strength Cond Res 
      31(12): 3463-3473, 2017-Various thresholds have been used to identify the onset 
      of contraction during isometric midthigh pull (IMTP); however, no agreed onset 
      threshold exists for this assessment. The purpose of this study was to compare 
      relative body weight (BW) and arbitrary onset thresholds to a criterion onset 
      threshold 5 SDs of BW for IMTP force-time variables; force at each threshold, 
      peak force, time-specific force values (100, 150, and 200 ms), and rate of force 
      development (RFD) during 0-100, 0-150, 0-200 ms. Academy rugby league players (n 
      = 9, age: 18.5 +/- 0.4 years; height: 1.82 +/- 0.09 m; mass: 91.2 +/- 13.1 kg) 
      performed 2 IMTP trials on a force platform sampling at 1,000 Hz. The neutral 
      force-time data pool (18 trials) was analyzed with five different thresholds and 
      compared with criterion threshold to determine any variance in force-time 
      variables. Five SDs of BW were significantly lower than 10% BW and 75 N for 
      threshold force which led to significantly greater time-specific force values at 
      100 and 150 ms and unacceptable limits of agreements (LOA) for all force-time 
      variables. No significant differences (p > 0.05) were observed between 2.5% and 5 
      SDs of BW; and between 5% and 5 SDs of BW for threshold force and all force-time 
      variables with acceptable LOA. The 5 SDs of BW and 2.5% BW onset thresholds 
      consistently resulted in the lowest values for threshold force, time-specific 
      force values, and RFD, attributed to a lower onset bias. Therefore, scientists 
      and practitioners are recommended to use a 5 SD of BW onset threshold for 
      time-specific force values and RFD for accurate data because it accounts for 
      signal noise during the weighing period. Subsequently, there is greater certainty 
      that the onset of contraction identifies a true meaningful change in force, in 
      contrast to relative BW thresholds.
FAU - Dos'Santos, Thomas
AU  - Dos'Santos T
AD  - Human Performance Laboratory, Directorate of Sport, Exercise, and Physiotherapy, 
      University of Salford, Greater Manchester, United Kingdom.
FAU - Jones, Paul A
AU  - Jones PA
FAU - Comfort, Paul
AU  - Comfort P
FAU - Thomas, Christopher
AU  - Thomas C
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Strength Cond Res
JT  - Journal of strength and conditioning research
JID - 9415084
SB  - IM
MH  - Adolescent
MH  - Body Weight
MH  - Football/*physiology
MH  - Humans
MH  - Isometric Contraction/*physiology
MH  - Male
MH  - Muscle Strength/*physiology
MH  - Muscle, Skeletal/*physiology
MH  - Resistance Training
MH  - Thigh/*physiology
MH  - Young Adult
EDAT- 2016/12/22 06:00
MHDA- 2018/06/05 06:00
CRDT- 2016/12/22 06:00
PHST- 2016/12/22 06:00 [pubmed]
PHST- 2018/06/05 06:00 [medline]
PHST- 2016/12/22 06:00 [entrez]
AID - 10.1519/JSC.0000000000001765 [doi]
PST - ppublish
SO  - J Strength Cond Res. 2017 Dec;31(12):3463-3473. doi: 
      10.1519/JSC.0000000000001765.