A Comparison Between the Traditional and Novel Isometric Mid-Thigh Methods and The Relationship to Countermovement Jump Performance

Abstract

The isometric mid-thigh pull (IMTP) test using the traditional bar grip (BAR) is a reliable and effective measure of strength performance in different populations. In addition, IMTP performance has been linked to jump performance. Recent research has shown that the pelvic belt (PEL) IMTP method produces higher absolute and relative peak force values than the Bar IMTP method. However, limited scientific data has examined the PEL IMTP method performance data and its relationship to dynamic strength and sports performance. The study aimed to provide a more robust comparison between the BAR and PEL IMTP methods and examine the relationship between these methods and several countermovement jump (CMJ) performance variables. Thirty healthy National Collegiate Athletic Association (NCAA) Division III athletes volunteered for this study. Each participant was asked to attend and complete four separate lab sessions utilizing a bilateral force platform. The results of this study demonstrated that peak force and relative peak force were significantly (p ≤ .05) greater during the PEL IMTP method than during the BAR IMTP method. Further, force development increased similarly in both the BAR and PEL IMTP methods, although there were no differences between the methods (p>.05). Lastly, Pearson's product-moment correlations demonstrated a medium and significant (p ≤ .05) relationship between CMJ and PEL IMTP variables. In conclusion, the PEL IMTP can measure lower body force performance capabilities. Further, PEL IMTP variables can be used to predict jump performance and, therefore, may be used for assessment and training purposes.

Introduction

The isometric mid-thigh pull (IMTP) is a popular and well-accepted method of measuring force output in the laboratory or in the training environment of various population groups using a portable force plate fitted with strain gauges or load cells.1,2 The traditional (BAR) IMTP method requires an individual to pull on a fixed barbell for 3–5 seconds with a maximal effort.3 The BAR IMTP method is valid and reliable, and in contrast to traditional repetition maximum (RM) testing, it is less physically demanding, offers a lower risk of injury, and provides a comprehensive range of metrics associated with athletic performance.1,4–7 These measures include but are not limited to maximum force production, force at different time epochs, time to a maximum rate of force development (RFD), and impulse at various time intervals.6,8 Furthermore, numerous studies have established a direct link between BAR IMTP method performance and lower body RM performance, as well as sports performance measures such as countermovement jump (CMJ) peak force, peak power, and jump height.8–14 Further, it has been suggested that increased force output in IMTP often correlates with greater peak power in the CMJ, as strength is a fundamental component of explosive power.13,14

The BAR IMTP method requires using both the lower and upper extremities and the trunk to pull a bar.3 This requires a coordinated pull that may be affected by muscle weakness or dysfunction in the upper body.15 As such, an alternative method has been suggested, the pelvic belt method (PEL), which uses a modified dip belt attached around the waist, thereby eliminating the need to use the upper extremity to complete the pull.15 Like the BAR IMTP method, the PEL IMTP participants also stand on a force plate. A study using a portable force plate found that the PEL IMTP method resulted in a 65% higher peak force than the traditional BAR IMTP method. The two methods showed a moderate correlation, r = 0.558 and 0.761, for days one and two, respectively. In addition, both methods exhibited good randomized repeated measures test-retest reliability, ICC (2,2) = 0.96 and 0.82, respectively, for the BAR and PEL IMTP methods. The authors suggested that while the PEL IMTP method requires only lower body joint involvement, its unfamiliar movement pattern may affect user comfort and ease of use.15

To date, only a limited amount of scientific data has examined the PEL IMTP method performance data and its relationship to dynamic strength and sports performance. To the best of our knowledge, there has been only one study that has examined the reliability of BAR and PEL IMTP methods.15 However, that study only reported correlations, test-retest reliability, and peak force data and did not examine results in relation to sports performance. In addition, a pilot study that we recently published compared the BAR and PEL methods and reported some performance metrics but did not examine the relationship between the BAR and PEL IMTP methods and sports performance 16. Therefore, the current study aims to provide a more robust comparison between the BAR and PEL IMTP methods and examine the relationship between PEL IMTP method and several CMJ performance variables. We hypothesize that the participants will significantly perform better utilizing the PEL IMTP than the BAR IMTP and that the PEL IMTP performance variables will significantly correlate with CMJ performance variables.

Methods

Participants

Thirty healthy National Collegiate Athletic Association (NCAA) Division III athletes, 15 males and 15 females (age = 20.00 ± 1.2 yr, height = 1.71 ± 0.10 m, weight = 69.36 ± 10.13 kg, BMI = 23.00 ± 2.61 kg·m⁻²) free of any cardiovascular, metabolic, neurological or physical impairment volunteered for this study. Each participant completed a physical activity readiness questionnaire (PAR-Q)17 and a medical history form, received a detailed explanation of the study's benefits and risks, and gave their written informed consent. We conducted a power analysis utilizing G*POWER 3.1.9.7 (Universitat Kiel, Germany) software to determine the sample size required for this study based on a pilot study with similar aims and outcomes 16. The effect size (1.34), power (95), and alpha level (0.05) used in the power analysis indicated that a sample of 10 was required, but we used 30 participants. All experimental procedures were conducted at the Laboratory of Applied Physiology (LAP) at North Carolina Wesleyan University (NCWU) and were approved by the NCWU Institutional Review Board for Human Participants Experimentation. Further, all experimental procedures followed the ethical standards set by the International Journal of Exercise Science.18

Protocol

Each participant was asked to attend and complete four separate lab sessions. During each testing session, a bilateral force platform sampling at 1000 Hz (HawkinDynamics, Westbrook, ME) was used for data collection utilizing HawkinDynamics software. During the IMTP, the force platform was placed on a Yucca Isometric Rig (Samson, Las Cruces, NM) with an immovable bar. The bar height was adjusted to position participants of different heights. On day one, documentation was completed, and anthropometric measures were collected. In addition, participants became familiarized with the bar grip (BAR) and pelvic belt (PEL) methods for the IMTP test and a countermovement jump (CMJ) test. In the second, third, and fourth lab sessions, the participants were assigned to complete the BAR, the PEL methods of the IMTP test, and the CMJ test. The order of the testing was counterbalanced and randomly assigned. Each visit lasted approximately 30 minutes. All visits were scheduled at least 24 hours apart and completed within 10 to 14 days.

Anthropometry

Body mass was measured to the nearest 20 g (Ohaus Champ II Model CH 150 R11, Ohaus Corporation, Florham Park, New Jersey, USA), and height was measured to the nearest 0.1 m using a stadiometer.

BAR IMTP Method

Upon arriving at the LAP, the participants were asked to complete a standardized warm-up protocol described by Comfort and colleagues.3 The warm-up consisted of 5-minutes of unloaded cycling on a Monark leg ergometer (Monark ergometer, Monark 828 E; Lindingo, Sweden) at 50 rpm and 10 bodyweight lunges and squats. The participants were then asked to perform submaximal trials of the IMTP at 50%, 75%, and 90% of maximal effort. For the test, the participants were asked to step onto the rig. To assume the correct body position, the participant's hip angles were measured between 140–150°, while knee angles were measured between 125 to 145° with feet approximately hip-width apart. The participants were strapped to a fixed bar in a clean hand position, shoulder-width apart 19 (Figure 1A). To start the test, the tester counted “3,2,1 and waited for the beep.” Once the beep was heard, the participant pushed as hard and as fast as possible, for approximately 5 seconds, into the ground. At least two trials were collected, and the acceptable trial with the highest peak force was used in this investigation. As suggested by Comfort et al,3 we inspected the force times curves, and the acceptable trials that were used were the ones with <250 N difference in peak force, with minimal pre-tension (<50 N) or countermovement at the start of the movement.

Figure 1.

Starting position for the (A) BAR IMTP and the (B) PEL IMTP.

PEL IMTP Method

Upon arriving at the LAP, the participants were asked to complete a standardized warm-up protocol similar to the one described above. For the test, the participants were asked to step onto the rig. To assume the correct body position, the participant's hip angles were measured between 140–150°, while knee angles were measured between 125 to 145° with feet approximately hip-width apart. The participants utilized a nylon six-inch-wide lifting belt and a 1” ratchet tie-down strap (Stanly, New Britain, CT) connected to the base of the rig (Figure 1B). The position of the lifting belt was standardized, centered above the hips and below the ribcage, allowing for free movement without restricting breathing. To start the test, the tester counted “3,2,1 and waited for the beep.” Once the beep was heard, the participant pushed as hard and as fast as possible, for approximately 5 seconds, into the ground. Similar to the BAR IMTP, at least two trials were collected, and the acceptable trial with the highest peak force was used in this investigation. As suggested by Comfort et al 3, we inspected the force times curves, and the acceptable trials that were used were the ones with <250 N difference in peak force, with minimal pre-tension (<50 N) or countermovement at the start of the movement.

CMJ Test

Upon arriving to the LAP, the participants were asked to complete a standardized warm-up protocol similar to what was described above. To start the test, the participants were asked to step on the force plates. Then, the tester counted “3,2,1 and waited for the beep.” Once the beep was heard, the participants were asked to perform a countermovement by dropping into an approximate squat position and then jump as high as possible with their hands remaining on their hips. Once the jump test was completed, participants were asked to step off the plates. The test was repeated three times with one minute between each attempt. The best vertical jump performance, based on jump height,20 was used for analysis.

Statistical Analysis

Means and standard deviation were used to describe the physical and anthropometric characteristics and the participants' neuromuscular and performance measures. All force values were corrected to compare the two methods, and only the force produced by the movement (net force) was counted.7–9 Individual dependent t-tests were used to evaluate differences between BAR and PEL IMTP variables. A Bonferroni correction was applied to eliminate the possibility of type I errors in the pairwise comparison. Also, for the individual dependent t-tests, Cohen’s d effect size statistics were calculated. The values were interpreted as 0–0.2, 0.2–0.6, 0.6–1.2, and 1.2–2.0 to be considered trivial, small, medium, and large effects, respectively.21 The Shapiro-Wilk test was performed to verify the normality of force data at various time epochs between BAR and PEL IMTP methods. A subsequent Wilcoxon Signed Ranks Test was used to compare the IMTP methods. Pearson product-moment correlation coefficients were used to examine any significant correlations between PEL IMTP and BAR IMTP force, power performance variables, and CMJ performance. Associations were defined as small, 0.1–0.3 (positive or negative); medium, 0.3–0.5 (positive or negative); large, 0.5–1.0 (positive or negative). In addition, we compared the PEL-CMJ Pearson product-moment correlation coefficients to the BAR-CMJ Pearson product-moment correlation coefficients using Fisher’s r-to-z transformation.22 Statistical significance was set at P ≤.05 for this investigation. All statistical analyses were performed using a statistical software package (SPSS, Version 29.0, SPSS, Inc., Chicago, IL).

Results

IMTP Performance

The participant's hip and knee angles were not significantly different (p >.05), 141.30 ± 2.83° versus 139.10 ± 4.00° and 141.93 ± 2.92° versus 141.03 ± 1.96° for the BAR and PEL IMTP, respectively. Peak force, relative peak force, Force Δ between 250 ms, and peak impulse 0–50, and 0–100 were significantly greater (p ≤.05) in the PEL IMTP method compared to the BAR IMPT method, with a medium effect size. The other variables were not significantly different (p >.05) between the IMTP methods and only demonstrated a trivial or small effect size (Table 1).

Table 1.

Differences between BAR and PEL IMTP variables.

Variable	BAR IMTP	PEL IMTP	P Value	ES
Length of Pull (S)	4.15 ± 0.43	4.25 ± 0.53	NS	−0.14
Time to Peak Force (S)	1.56 ± 0.97	1.62 ± 0.88	NS	−0.06
Peak Force (N)	950.53 ± 323.95	1290.47 ± 678.55	< 0.001	−0.76
Relative Peak Force (N·kg−1)	13.34 ± 4.60	18.42 ± 9.20	< 0.001	−0.72
Force Δ between 250 ms and peak (N)	307. 67 ± 174.14	562. 77 ± 363.52	< 0.001	−0.75
RFD 0–50 ms (N·s−1)	3309.33 ± 2672.92	4284.00 ± 3535.31	NS	−0.43
RFD 0–100 ms (N·s−1)	3200. 33 ± 1932.50	3658.67 ± 2812.82	NS	−0.29
RFD 0–150 ms (N·s−1)	3183.30 ± 1483.16	2920.23 ± 2199.24	NS	−0.17
RFD 0–200 ms (N·s−1)	2924.67 ± 1279.29	2862.17 ± 2035.16	NS	−0.05
RFD 0–250 ms (N·s−1)	2424.40 ± 1046.23	2910.80 ± 1866.39	NS	−0.41
Peak RFD (N)	4643.33 ± 2390.04	4788. 00 ± 3281.12	NS	−0.06
Time to Peak RFD (ms)	125.00 ± 53.74	123.33 ± 85.83	NS	−0.06
Impulse 0–50 (Ns)	46.30 ± 9.91	50.33 ± 13.10	< 0.001	−0.63
Impulse 0–100 (Ns)	100.57 ± 23.29	110.83 ± 32.00	< 0.001	−0.63
Impulse 0–150 (Ns)	162.85 ± 38.35	176.20 ± 53.93	NS	−0.49
Impulse 0–200 (Ns)	230.34 ± 54.78	246.75 ± 78.81	NS	−0.40
Impulse 0–250 (Ns)	303.72 ± 71.88	324.84 ± 107.01	NS	−0.37

BAR IMTP: traditional isometric mid-thigh pull method; PEL IMTP: pelvis belt isometric midthigh pull method; RFD: rate of force development; NS: not significant; ES: Effect Size

The force differences between BAR and PEL IMPT across five-time epochs

A Wilcoxon signed-rank test showed a nonsignificant difference between the BAR and PEL IMTP methods' force time epochs (Z = −972, p = 0.331) (Figure 2).

Figure 2.

Force differences between BAR and PEL IMPT across five-time epochs.

The relationship between PEL IMTP and CMJ performance variables

The results from Pearson’s product-moment correlation revealed a medium and significant (p ≤ .05) relationships between PEL IMTP peak force and CMJ jump height (Figure 3A), CMJ peak power (Figure 3B), and CMJ peak force (Figure 3C).

Figure 3.

The relationship of PEL IMTP peak force and CMJ Jump Height (A), Peak Power (B), and Peak Force (C).

Pearson’s product-moment correlation demonstrated a medium and large, and significant (p’s ≤ .05) relationship between CMJ peak force, peak power, jump height, and PEL IMTP, force at different time epochs, RFD, and impulse at different time periods. The relationship between CMJ peak power and jump height and PEL IMTP force at 100 ms and CMJ peak power and force at 250 ms and the relationship between peak force and impulse at 0–50, 0–100, and 0–150 were not significantly (p’s >.05) correlated (Table 2).

Table 2.

Pearson Product Moment Correlations (r) between PEL IMTP force at various time epochs and RFD and CMJ performance variables.

Variable	CMJ PF	CMJ PP	CMJ JH
PEL IMTP F50	0.48**	0.39*	0.37*
PEL IMTP F100	0.49**	0.29	0.28
PEL IMTP F150	0.52**	0.39*	0.39*
PEL IMTP F200	0.51**	0.45*	0.43*
PEL IMTP F250	0.42*	0.35	0.36*
PEL IMTP RFD 0–50	0.43*	0.56**	0.53**
PEL IMTP RFD 0–100	0.47**	0.52**	0.49**
PEL IMTP RFD 0–150	0.50**	0.46*	0.44*
PEL IMTP RFD 0–200	0.51**	0.49*	0.47**
PEL IMTP RFD 0–250	0.50**	0.51**	0.49**
PEL IMTP PRFD	0.41*	0.55**	0.52**
PEL IMTP Imp 0–50	0.24	0.75**	0.65**
PEL IMTP Imp 0–100	0.32	0.75**	0.66**
PEL IMTP Imp 0–150	0.35	0.72**	0.64**
PEL IMTP Imp 0–200	0.38*	0.70**	0.63**
PEL IMTP Imp 0–250	0.40*	0.69**	0.62**

PEL: pelvis belt method; CMJ: countermovement jump; PF: peak force; PP: peak power; JH: jump height; IMTP: isometric mid-thigh pull; RFD: rate of force development; PRFD: peak rate of force development; Imp: impulse;

^**p ≤ .01;

^*p ≤ .05

The relationship between BAR IMTP and CMJ performance variables

The results from Pearson’s product-moment correlation revealed a medium and significant (p ≤ .05) relationship between BAR IMTP peak force and CMJ jump height (r = 0.38; p = 0.38) and CMJ peak power (r = 0.39; p = 0.32). The relationship between BAR IMTP peak force and CMJ peak force was not significant (p > .05).

Comparing the PEL-CMJ to the BAR-CMJ Pearson product-moment correlation coefficients using Fisher’s r-to-z transformation

The Fisher’s r-to -z-transformation test results showed that the PEL-CMJ correlations were stronger than the BAR-CMJ correlations for IMTP peak force and CMJ Jump Height (PEL IMTP = 0.47 versus BAR IMTP =0.40), Peak Power (PEL IMTP = 0.46 versus BAR IMTP =0.41), and Peak Force (PEL IMTP = 0.50 versus BAR IMTP =0.38).

Discussion

To the best of our knowledge, the present investigation is the first to comprehensively compare the BAR and the PEL IMTP methods. In addition, our study is the first to examine the relationship between PEL IMTP performance and CMJ performance. The results of this study demonstrated that peak force and relative peak force were significantly greater during the PEL IMTP method than during the BAR IMTP method (Table 1). Further, force development increased similarly in both the BAR and PEL IMTP methods, although there were no differences between the methods (Figure 2). Furthermore, product-moment correlations demonstrated a medium and significant relationship between CMJ peak force, peak power, jump height, and PEL IMTP force, force at different time epochs, RFD, and impulse (Figure 3 and Table 2). Lastly, Fisher’s r-to -z-transformation test results showed that the PEL-CMJ correlations were stronger than the BAR-CMJ correlations for IMTP peak force and CMJ Jump Height, Peak Power, and Peak Force.

As suggested by Comfort et al,3 we measured and ensured that knee and hip angles were within the recommended range to minimize postural differences between the methods. Although the length of the pull and time to peak force were similar (p >.05) between the IMTP methods, 4.15 versus 4.25 s and 1.56 versus 1.62 s, for the BAR and PEL IMTP, respectively, the PEL IMTP method yielded a significantly higher (p ≤ .05) peak force and relative peak force than the BAR IMTP method (Table 1). This finding is similar to Williams and colleagues, although they reported higher absolute PEL IMTP peak force values than our findings, ~2300 N versus ~1290 N 15. The difference seems to be related to the data analysis process. As we mentioned previously, the force values in our investigation were corrected to compare the two methods, and only the force produced by the movement (net force) was counted. This technique has been used by others,7–9 allowing for nullifying artificial differences to prevent skewed results between the methods.

It is possible that differences in muscle recruitment between the two movements could explain the differences between the methods' peak and relative peak forces (Table 1). The BAR IMTP method involves the lower and upper extremities and the trunk pulling the bar.3 Specifically, the lower extremities contribute to force production, while the upper extremities provide stability and balance. Conversely, the PEL IMTP method does not utilize the upper extremities and relies solely on the lower extremities and trunk to pull the bar.15,16 Since the upper body musculature is typically smaller in mass and size than the lower body,23,24 it is plausible that the upper body muscles experience fatigue earlier. The PEL IMTP, relies exclusively on the larger lower body major muscle groups, such as the quadriceps, glutes, and hamstrings groups, which have greater muscle mass and fiber CSA and, therefore, can generate more force and are more fatigue resistant.24–27 It is important to note that we did not measure CSA or the electrical activity of the muscles through electromyography (EMG) to assess muscle recruitment; therefore, this hypothesis is speculative.

A closer inspection of the force at different time epochs, RFD, and impulse data reveals that there that was only slight and insignificant (p >.05) differences between BAR and PEL IMTP in the first 250 ms of the movement (Figure 3 and Table 1). However, we observed significant (p ≤ .05) force differences between the force at 250 ms and peak force in the PEL IMTP compared to the BAR IMTP (Table 1). This finding is interesting and supports our hypothesis that the differences between the methods may be attributed to the upper extremity musculature fatigue in the BAR IMTP. When comparing the BAR and the PEL methods, the force comes from the larger major muscle groups in the lower body. However, in the BAR IMTP method, the athletes must maintain the isometric pull with upper body muscles, whereas, in the PEL IMTP method, the isometric pull is exclusively held by the lower body muscle groups. Therefore, as mentioned before, fatigue of the upper body muscles is probable and may lead to differences in force generation between the methods.

Another plausible difference between the PEL IMTP and BAR IMTP that may affect peak and relative peak forces may stem from the biomechanics of each method. Biomechanically, the PEL IMTP resembles the hex bar deadlift more closely, as the load is positioned nearer to the body's center of gravity. This alignment shortens the horizontal distance between the load and reduces the resistance moment arm.28 In contrast, the BAR IMTP is more similar to the straight bar deadlift, where the force applied to the bar is positioned farther in front of the body, resulting in a longer resistance moment arm.28 Considering the biomechanical similarities between the PEL isometric mid-thigh pull (IMTP) and the hex bar deadlift, as well as between the BAR IMTP and the straight bar deadlift, it is not surprising that studies supporting these two deadlift methods align with our findings.28–30 Specifically, peak force and relative peak force were significantly greater during the PEL IMTP method compared to the BAR IMTP method. Camara et al. 29 tested men with deadlifting experience and found that using the hex bar was more effective for developing maximal force compared to the straight bar. Swinton and colleagues 28 demonstrated that the differences in biomechanics and muscle activation patterns between the two bars resulted in significantly greater peak force when using the hex bar across various submaximal loads. Finally, Lockie et al30 studied 31 strength-trained subjects who performed a one-repetition maximum (1RM) deadlift and found that the hex bar produced greater mean and peak force compared to the straight bar. They suggested that this might be due to the biomechanical differences, which allow for reduced displacement and enable heavier 1RM loads when using the hex bar.

One of the key objectives of this study was to explore the relationship between the PEL IMTP method PF and CMJ performance variables. The current investigation has revealed that PEL IMTP peak force is moderately and significantly associated with CMJ JH, PP, and PF (Figure 2 A, B, and C). Furthermore, a Fisher’s r-to -z-transformation test results showed that PEL IMTP peak force, when compared to BAR IMTP peak force, displays a stronger correlation to CMJ Jump Height (PEL IMTP = 0.47 versus BAR IMTP =0.40), Peak Power (PEL IMTP = 0.46 versus BAR IMTP =0.41), and Peak Force (PEL IMTP = 0.50 versus BAR IMTP =0.38). Our findings are supported by others that showed a similar relationship between BAR IMTP and CMJ performance. Several investigations have examined the relationship between BAR IMTP PF and CMJ PF, PP, and JH, showing medium to large associations, r > 0.3.8–10 For Instance, Stone et al. 8 conducted a study with 30 competitive sprint cyclists and found a strong correlation between BAR IMTP and CMJ JH and PP, r = 0.59 and r = 0.79, respectively. Similarly, Kawamori and colleagues10 examined this relationship in eight college-age weightlifters and showed a strong correlation between BAR IMTP PF and CMJ PF and PP, r = 0.87 and r = 0.95, respectively. In line with the BAR IMTP, our study suggests that the PEL IMTP PF can also be a reliable predictor of jump performance, which could have significant implications for testing and training purposes.

Similar to the relationship between PEL IMTP method PF and CMJ performance variables, a relationship is apparent between PEL IMTP method force at different time epochs, peak RFD, and RFD and impulse at various time intervals, and CMJ performance variables (Table 2). It is important to note that some of the variables we examined and are mentioned in the correlation analysis are not mentioned in the literature, for example, F150, F200, RFD at various time intervals, imp 0–50 and imp 0–250 (Table 2). Although there are differences between BAR and the PEL IMTP methods, our findings are similar to others that have demonstrated that other BAR IMTP performance variables correlate well with CMJ variables.9,11–14 Kraska et al11 examined 63 collegiate athletes and showed that force at various times along the force-time curve was associated with CMJ height. Similarly, West 14 and colleagues demonstrated a significant correlation, r = 0.55, between force at 100 ms and CMJ PP. Several studies have examined the relationship between BAR IMTP PRFD, CMJ PP, and jump height and demonstrated significant, large and medium correlations, 0.65–0.81 and 0.39, respectively.9,12 Others examining the relationship between BAR IMTP and impulse values across different time epochs in collegiate athletes reported medium to large correlations, 0.49–0.64, between BAR IMTP IMP 100 ms, 200 ms, and 300 ms and CMJ PF and PP.13 Similar to the BAR IMTP PF, our findings imply that other PEL IMTP variables (Table 2) can be used to predict jump performance and can potentially be used for assessment and training purposes.

It is important to acknowledge that this study has several limitations. While we compared two different IMTP methods, our focus was primarily on differences in performance and how they relate to the Countermovement Jump (CMJ). We did not investigate the biomechanical differences between the two methods or muscle activation and recruitment patterns. Future research should explore these aspects further to better differentiate between the two IMTP methods.

Overall, the results of the study indicate that although the length of pull and time to peak force were similar (p >.05) between the IMTP methods, the PEL IMTP method yielded a significantly higher (p ≤.05) peak force and relative peak force than the BAR IMTP method. Examining RFD and impulse data, as well as force development from 250 ms to peak force, indicate that the differences between the methods may be related to biomechanical differences and events that occur later in the movement and may be attributed to the fatigue of the upper extremity musculature in the BAR IMTP. Further, Pearson’s product-moment correlation demonstrated a medium, large, and significant (p ≤.05) relationship between CMJ variables and selected PEL IMTP variables such as PF, force at different time epochs, RFD, and impulse at different periods. In conclusion, the results of the study indicate that the PEL IMTP provides mostly similar results as the traditional BAR IMTP in the determination of lower body force performance capabilities. In addition, PEL IMTP variables can be used to predict jump performance, highlighting the test potential for assessment and training purposes.