Isometric Midthigh Pull Reliability and Relationship to Deadlift One Repetition Maximum

Abstract

De Witt, JK, English, KL, Crowell, JB, Kalogera, KL, Guilliams, ME, Nieschwitz, BE, Hanson, AM, and Ploutz-Snyder, LL. Isometric midthigh pull reliability and relationship to deadlift one repetition maximum. J Strength Cond Res 32(2): 528-533, 2018-The purpose of this investigation was to examine the reliability of the isometric midthigh pull (IMTP) and the relationship between IMTP peak force and deadlift 1 repetition maximum (1RM). Nine subjects (5 men and 4 women; 40.6 ± 8.0 years; 1.72 ± 0.10 m; 75.6 ± 13.4 kg) participated in this study. Isometric midthigh pull and deadlift 1RM were both performed during 2 testing sessions. For IMTP, peak force and peak rate of force development (RFD) were determined, in addition to RFD at 30 ms, 50 ms, 90 ms, 150 ms, 200 ms, and 250 ms after initiation of the pull. Intraclass correlation coefficients (ICCs) were calculated to evaluate the reliability of IMTP measures. Pearson product-moment correlations and linear regression were used to determine associations between IMTP and deadlift 1RM. Isometric midthigh pull peak force was reproducible both within (ICC = 0.98 and 0.97) and between sessions (ICC = 0.89) and significantly correlated with deadlift 1RM (r = 0.88, p ≤ 0.05), but intermediate force outputs and RFD were not. Lack of associations between RFD and deadlift 1RM indicate that the ability to create explosive force may be independent of the ability to create maximal force. The strong relationship between IMTP peak force and deadlift 1RM was present regardless of which IMTP repetition across the 2 sessions was examined. Peak force generated during IMTP is a reliable method to assess full body maximal strength. A single IMTP repetition, provided adequate familiarization and warm-up, correlates strongly with deadlift 1RM. Practitioners can use the IMTP test as a method to estimate maximal deadlift strength in a quick and potentially less provocative manner than traditional 1RM testing.

The Effect of Hip Joint Angle on Isometric Midthigh Pull Kinetics

“…Therefore, coaches and researchers are advised to specify and standardise their knee and hip joint angles adopted for IMTP testing and state whether absolute or relative joint angles were measured to avoid confusion and allow the replication of IMTP testing methodologies. **Insert Figure 2 about here** The present study found PF to demonstrate the highest between-session reliability measures for both postures (Table 2) similar to the observations of previous between-session (ICC ≥ 0.89 , CV ≤ 4.6%) (8,11,15,45) and within-session research (ICC ≥ 0.97 , CV ≤ 3.2%) (12,22). Equally, both postures demonstrated high levels of within-session reliability for timespecific force values (Table 1) comparable to the reliability measures reported in previous research (4,12,22,29).…”

“…The IMTP is commonly used to assess the peak force (PF) production but a further advantage is the ability to inspect an athlete's ability to produce force (4,12,15,22), rate of force development (RFD) (4,12,22) and impulse (8,43) at critical time intervals. The IMTP has been shown to demonstrate high within-and between-session reliability measures for PF (8,11,14,15,22), time-specific force values (4,12,15,22), rate of force development (12,22) and impulse (8,43) across different time intervals. Due to the high reliability and its simplicity to administer, the IMTP is commonly used to evaluate the force-time qualities to prescribe future training such as inspection of the dynamic strength index when combined with PF during a jump (45); while also used to monitor adaptations to training (3).…”

“…Due to the high reliability and its simplicity to administer, the IMTP is commonly used to evaluate the force-time qualities to prescribe future training such as inspection of the dynamic strength index when combined with PF during a jump (45); while also used to monitor adaptations to training (3). Additionally, the IMTP can be used as a potentially safer surrogate to dynamic one repetition maximum (1RM) strength testing (8,11), with strong correlations observed between IMTP PF and 1RM back squat (r ≥ 0.96) (33,35), snatch and clean and jerk (r ≥ 0.83) (4) and deadlift (r = 0.88) (11). Moreover, inspecting neuromuscular preparedness (18) and assessment of bilateral (1) and unilateral force production asymmetries (13) are further purposes of IMTP testing.…”

Strength and Reaction Time Capabilities of New Zealand Polo Players and Their Association with Polo Playing Handicap

“…Isometric mid-thigh pull (IMTP) was assessed using a customised testing rig, consisting of two Pasco force plates (Roseville, California) and perpendicular vertical poles drilled at 1 cm increments to allow appropriate grip adjustment and positioning of the bar to the participants' mid-thigh. Intraclass correlation coefficient (ICC) statistics in similar protocols have shown reliable measures both within (ICC = 0.97) and between (ICC = 0.89) sessions [23]. A demonstration of the IMTP was provided by the researcher prior to the first trial, and participants had an opportunity to practise the hand grip placement and pulling position prior to commencement.…”

Familiarisation, reproducibility, sensitivity and joint angle specificity of bilateral isometric force exertions during leg press

“…Isometric multi-joint tests are a common method of assessing maximal force capacity. There are numerous lines of enquiry that have used squat [4][5][6][7] and mid-thigh pull [8][9][10] exercises.…”