THE ISOMETRIC MIDTHIGH PULL (IMTP) IS COMMONLY USED TO ASSESS AN ATHLETE'S FORCE GENERATION ABILITY. THIS TEST IS HIGHLY RELIABLE AND IS SIMPLE AND RELATIVELY QUICK TO PERFORM. THE DATA THAT CAN BE DETERMINED FROM THE FORCE–TIME CURVES GENERATED BY THE TEST HAVE BEEN SHOWN TO BE CLOSELY RELATED TO PERFORMANCE CAPACITIES IN A VARIETY OF DYNAMIC ATHLETIC TASKS. HOWEVER, WITHIN THE SCIENTIFIC LITERATURE, THERE ARE INCONSISTENCIES IN THE DATA COLLECTION PROCEDURES AND METHODS USED FOR DATA ANALYSIS THAT MAY IMPACT THE RESULTANT OUTPUT AND THE ABILITY TO COMPARE AND GENERALIZE RESULTS. THEREFORE, THE PRIMARY AIM OF THIS REVIEW IS TO IDENTIFY THE DIFFERENCES IN IMTP TESTING PROCEDURES AND DATA ANALYSIS TECHNIQUES, WHEREAS IDENTIFYING THE POTENTIAL IMPACT THIS MAY HAVE ON THE DATA COLLECTED. THE SECONDARY AIM IS TO PROVIDE RECOMMENDATIONS FOR THE STANDARDIZATION OF TESTING PROCEDURES TO ENSURE THAT FUTURE IMTP DATA ARE OF MAXIMAL BENEFIT TO PRACTITIONERS AND RESEARCHERS. FOR A VIDEO ABSTRACT OF THIS ARTICLE, SEE SUPPLEMENTAL DIGITAL CONTENT 1 (SEE VIDEO, HTTP://LINKS.LWW.COM/SCJ/A249).

Combat sports encompass a range of sports, each involving physical combat between participants. Such sports are unique, with competitive success influenced by a diverse range of physical characteristics. Effectively identifying and evaluating each characteristic is essential for athletes and support staff alike. Previous research investigating the relationship between combat sports performance and measures of strength and power is robust. However, research investigating the relationship between combat sports performance and assessments of endurance is less conclusive. As a physical characteristic, endurance is complex and influenced by multiple factors including mechanical efficiency, maximal aerobic capacity, metabolic thresholds, and anaerobic capacities. To assess endurance of combat sports athletes, previous research has employed methods ranging from incremental exercise tests to circuits involving sports-specific techniques. These tests range in their ability to discern various physiological attributes or performance characteristics, with varying levels of accuracy and ecological validity. In fact, it is unclear how various physiological attributes influence combat sport endurance performance. Further, the sensitivity of sports specific skills in performance based tests is also unclear. When developing or utilizing tests to better understand an athletes’ combat sports-specific endurance characteristic, it is important to consider what information the test will and will not provide. Additionally, it is important to determine which combination of performance and physiological assessments will provide the most comprehensive picture. Strengthening the understanding of assessing combat sport-specific endurance as a physiological process and as a performance metric will improve the quality of future research and help support staff effectively monitor their athlete’s characteristics.

The aim of this study was to assess the agreement of three different automated methods of identifying force-onset (40 N, 5 SDs, and 3 SDs) with manual identification, during the isometric mid-thigh pull (IMTP). Fourteen resistance-trained participants with >6 months experience training with the power clean volunteered to take part. After three familiarisation sessions, the participants performed five maximal IMTPs separated by 1 min of rest. Fixed bias was found between 40 N and manual identification for time at force-onset. No proportional bias was present between manual identification and any automated threshold. Fixed bias between manual identification and automated was present for force at onset and F₁₅₀. Proportional but not fixed bias was found for F₅₀ between manual identification and all automated thresholds. Small to moderate differences (Hedges g = −0.487- −0.692) were found for F₉₀ between all automated thresholds and manual identification, while trivial to small differences (Hedges g = −0.122—−0.279) were found between methods for F₂₀₀ and F₂₅₀. Based on these results, strength and conditioning practitioners should not use a 40 N, 5 SDs, or 3 SDs threshold interchangeably with manual identification of force-onset when analysing IMTP force–time curve data.

Velocity-based training (VBT) is an increasingly popular programming strategy used by strength and conditioning professionals to develop their athlete's ability to express force rapidly. To implement the varying forms of VBT effectively within their training regimes, strength and conditioning professionals need to understand the strengths and weaknesses of strategies, such as predicting 1 repetition maximum using the load-velocity profile, modulating training loads using the load-velocity profile, and controlling training volume using the magnitude of velocity-loss. The aim of this review was to highlight these strengths and weaknesses and then provide practical examples of when each programming strategy may be most effectively implemented.

Guppy, SN, Brady, CJ, Kotani, Y, Stone, MH, Medic, N, and Haff, GG. Effect of altering body posture and barbell position on the within-session reliability and magnitude of force-time curve characteristics in the isometric midthigh pull. J Strength Cond Res 33(12): 3252–3262, 2019—A large degree of variation in the position used during isometric midthigh pull (IMTP) testing and conflicting results of the effects of these changes can be found in the literature. This study investigated the effect of altering body posture and barbell position on the reliability and magnitude of force-time characteristics generated during the IMTP. Seventeen strength-power athletes (n = 11 males, height: 177.5 ± 7.0 cm, body mass: 90.0 ± 14.1 kg, age: 30.6 ± 10.4 years; n = 6 females, height: 165.8 ± 11.4 cm; body mass: 66.4 ± 13.9 kg, age: 30.8 ± 8.7 years) with greater than 6 months of training experience in the clean (1 repetition maximum: 118.5 ± 20.6 kg, 77.5 ± 10.4 kg) volunteered to undertake the experimental protocol. Subjects performed the IMTP using 4 combinations of hip and knee angles, and 2 different barbell positions. The first barbell position corresponded to the second pull of the clean, while the second rested at the midpoint between the iliac crest and the patella. Peak force (PF), time-specific force (F₅₀, F₉₀, F₁₅₀, F₂₀₀, and F₂₅₀), peak rate of force development (pRFD), and impulse (IMP) time bands were reliable in all 4 testing positions examined. Statistically greater PF, F₅₀, F₉₀, F₁₅₀, F₂₀₀, F₂₅₀, pRFD, and IMP_0–50, IMP_0–90, IMP_0–150, and IMP_0–200 were generated in a testing position corresponding to the second pull of the clean when compared with a bent over torso angle, regardless of the barbell position used. Moderate to large effect sizes favoring a testing position corresponding to the second pull were also found. Overall, when performing the IMTP, an upright torso and a barbell position that matches the second pull of the clean should be used.

Seventeen strength and power athletes (n = 11 males, 6 females; height: 177.5 ± 7.0 cm, 165.8 ± 11.4 cm; body mass: 90.0 ± 14.1 kg, 66.4 ± 13.9 kg; age: 30.6 ± 10.4 years, 30.8 ± 8.7 years), who regularly performed weightlifting movements during their resistance training programs, were recruited to examine the effect of altering body posture and barbell position on the between-session reliability of force-time characteristics generated in the isometric mid-thigh pull (IMTP). After participants were familiarised with the testing protocol, they undertook two testing sessions which were separated by seven days. In each session, the participants performed three maximal IMTP trials in each of the four testing positions examined, with the order of testing randomized. In each position, no significant differences were found between sessions for all force-time characteristics (p = >0.05). Peak force (PF), time-specific force (F50, F90, F150, F200, F250) and IMP time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) were reliable across each of the four testing positions (ICC ≥ 0.7, CV ≤ 15%). Time to peak force, peak RFD, RFD time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) and peak IMP were unreliable regardless of the testing position used (ICC = 15%). Overall, the use of body postures and barbell positions during the IMTP that do not correspond to the second pull of the clean have no adverse effect on the reliability of the force-time characteristics generated.