The National Strength and Conditioning Association (NSCA) defines the deadlift as an exercise in which a barbell is lifted from the floor by extending the hips and knees until the body reaches a fully erect torso position, then the bar is lowered back to the floor (18). The deadlift has major applications in strength development programs because of the benefits derived from executing multijoint, ground-based closed kinetic chain movements (20). These benefits include high muscle activation of the trunk, lower, and upper extremity (2,7), improvements in peak power production from the increase in maximal strength (24), and improvements in functional movements and injury prevention implications (23).
As training loads used in the deadlift progress to maximum, repetition failure occurs, stalling progress. One causal factor of repetition failure in the deadlift is the “sticking point.” A sticking point is defined as the most strenuous movement of a repetition, typically occurring soon after the transition from the eccentric to concentric phase (18). The sticking point of an exercise can be seen with the initial decrease in vertical barbell velocity (15). Research trying to locate the sticking point of the conventional deadlift found that typically bar velocity began to decrease during the initial pull on the barbell, with the sticking point occurring below the knees of the lifter (14).
Training methods to overcome the sticking point in the deadlift are difficult to pinpoint because of a lack of research examining deadlift training protocols. Popular methods used in powerlifting to train the deadlift include the use of bands and chains (25–27) to increase resistance at the top portion of the lift, but this still neglects the weakness in the initial sticking point. Research indicates that the reduction in weight needed to clear the deadlift sticking point results in loads, which are not enough to elicit an overload stimulus at the upper portion of the deadlift (29). Developing a training technique to lift a heavier load through the sticking point could be an instrumental step in increasing 1 repetition maximum (1RM). One way to overcome the sticking point and thereby train the deadlift with heavier loads may be to perform the deadlift with an eccentrically loaded countermovement.
The eccentrically loaded deadlift is considered a variation of the conventional deadlift, and uses the benefit of eccentrically loading the musculature in an attempt to produce greater force (3,4) (i.e., the stretch shortening cycle [SSC]). In this movement, the SSC is incorporated by initiating the deadlift with the bar at an elevated position (i.e., eccentrically loading the musculature); then on contacting the floor, moving quickly from the eccentric (lowering) phase into the concentric (pulling) phase of the deadlift; hopefully moving through the sticking point with heavier weight and completing the full range of motion (ROM) of the lift.
The SSC is a scientific principle often manipulated in strength and power training, most commonly seen in the form of plyometrics (1). By incorporating counter movements, the SSC has been shown to acutely increase power output in movements such as the vertical jump (12). Based on the scientific principles behind the SSC and counter movements, and observations taken directly from strength training, the eccentrically loaded deadlift has merit as a potential full ROM training modality, which targets overcoming the sticking point in the conventional deadlift. This is in contrast to other popular training methods, which incorporate shortening the ROM of the exercise to lift more weight through a partial movement (29), but do not target the actual sticking point. Therefore, the primary purpose of this study was to determine if an eccentrically loaded deadlift will yield a higher 1RM and 3RM than a conventional deadlift initiated from the floor. If so, then heavier loads may be used through a full ROM deadlift during maximal strength development phases.
The secondary purpose of this study was to see if the 1RM conventional and eccentrically loaded deadlift can be accurately calculated based on the 3RM, where the 3RM is presumed to reflect 93% of 1RM (18). Percentage relationships are instrumental for determining optimal load and volume in training progressions. Much research has been dedicated to finding the optimal percentage chart, however, results from different research varies greatly between individuals and exercises (including upper and lower body exercises) (10,11). Additionally, when prescribing intensity percentages in the deadlift, a problem can arise in quantifying the movement as either an upper or lower body exercise. Because of the great amount of musculature activated during the deadlift (7), it could be argued that the deadlift is in fact a total body exercise. For this reason, more research is needed to establish training guidelines at different percentages of 1RM.
Experimental Approach to the Problem
To determine if an eccentrically loaded deadlift would result in higher loads lifted than a conventional deadlift and if the 1RM could be calculated based on the 3RM, this study used a randomized repeated measures cross-over design model. Subjects were randomly divided into groups, with the first group testing conventional deadlift the first week and eccentrically loaded deadlift the second week, whereas the second group was tested in the eccentrically loaded deadlift the first week and the conventional deadlift the second week. The independent variables tested in this study consisted of the eccentrically loaded and conventional deadlift. The dependent variable in this study was the amount of weight lifted by the participant.
The participants in this study were 15 freshman division 1 collegiate football players in their first year as active members of a year round, structured, collegiate training program (all had a minimum of 6 months of collegiate strength training and were experienced in the deadlift exercise), and all had previous strength training experience in their high school careers. The participants were redshirt freshmen who were involved in 4 practices a week with the team. Mean age was 20.3 ± 1.9 years (range, 18–25 years); mean mass was 95.8 ± 18.2 kg (range, 74.1–129.1 kg); mean height was 184.4 ± 6.6 cm (range, 172.7–195.6 cm). The participants were volunteers with no monetary compensation being provided. This study was approved by the University's Institutional Review Board, and all participants signed an informed consent before data collection.
Materials used in the study included the following standard items: a deadlift platform, Olympic barbell, free weights, chalk, weight collars, and plyometric boxes. Research supports the use of a standard Olympic-sized barbell to obtain highest 1RM values, while training the deadlift (19). Therefore, an Olympic-sized barbell was used to ensure optimal performance.
Participants were randomly assigned to 2 groups (n = 7; n = 8). After group assignment, participants were brought in the week before the first data collection to be familiarized with the testing protocol. After the testing protocol was explained, the participants practiced the testing procedure, until they felt comfortable with the conventional and eccentrically loaded deadlift exercises. During this familiarization meeting, the weight was kept at a moderate intensity (less than 50% of estimated 1RM), but the testing protocol was performed in the same manner the participants would encounter during the following 2 weeks of data collection. Next, one group was tested in the conventional deadlift week 1 and the eccentrically loaded deadlift week 2, whereas the other group was tested in the eccentrically loaded deadlift week 1 and the conventional deadlift in week 2. An alternate (over/under grip) was used in all trials. Testing was conducted in the spring; test days were separated by 7 days and time of day was standardized. Participants were asked to not alter their normal nutrition and hydration routines during the test period.
The conventional deadlift was conducted using standards outlined by the NSCA (18) in which weight is lifted from the floor to an erect position and lowered back to the floor. The eccentrically loaded deadlift was initiated with the participant standing on the floor and the weighted barbell resting on a plyometric box. For each lifter, the bar was individually set to a height in which the lift was initiated with the bar halfway between the knee and thigh. The participant's first movement was to lift the bar off of the boxes to an erect standing position (as though performing a rack pull). As the participant lifted the bar from the boxes, 2 spotters moved the boxes such that they would not be in the path of the loaded bar during the execution of the remainder of the lift. From the erect standing position, the participant then lowered the bar to the floor (i.e., eccentrically loading the musculature), then on contacting the floor moving quickly (without bouncing) from the eccentric phase into the concentric pulling phase of the deadlift, passing through the sticking point, and completing the full ROM of the lift.
For both the conventional and eccentrically loaded deadlift, a warm-up set of 5–10 repetitions was performed using 40–60% of the estimated 1RM. After a 2–5-minute rest period, a set of 3 repetitions was performed at 60–90% of the estimated 1RM, and continued until a 3RM was achieved. Then, after a 5-minute rest, 3–4 maximal trials of 1 repetition were performed to determine the 1RM. Rest periods between trials lasted 2–5 minutes. A complete ROM and proper technique was required for a lift to be considered successful (i.e., each subject had to complete the repetition to full trunk extension, and they were not allowed to continue testing once a weight was reached that caused technical breakdown, which was considered head and shoulders tilting over the feet or little to no knee bend during extension). The test administrator (a trained strength professional with knowledge and experience in performing both eccentrically loaded and conventional deadlift RM testing) monitored each lift.
Pearson correlation coefficients (PCC) (r) and dependent t-tests were calculated to determine the statistical comparisons and correlations between and among the modalities (conventional deadlift [CD], eccentric deadlift [ED]). Pearson correlation coefficients were calculated to determine if there were positive relationships between the CD 1RM and the CD 3RM, CD 1RM and the ED 1RM, ED 1RM and the ED 3RM, CD 3RM and the ED 3RM, CD 1RM and the CD 1RM estimate, and ED 1RM and the ED 1RM estimate. Significance for these comparisons was set at α = 0.05 (one-tailed). Assuming an effect size of r ≥ 0.70 is meaningful, a desired power of 80% can be achieved with n = 10 participants (6). This study had a minimum of n = 13 for all comparisons.
Dependent t-tests were employed to determine if there were differences between CD 1RM and the ED 1RM, CD 3RM and the ED 3RM, CD 1RM and the CD 1RM estimate, and ED 1RM and the ED 1RM estimate. Significance for these comparisons was set at α = 0.05 (one-tailed). Assuming an effect size of 0.80 is meaningful, 80% power can be achieved with 13 participants (6).
The dependent variables measured in this study were 1RMs and 3RMs for the modalities of the CD and the ED. The NSCA recognizes 1RM and 3RM measures as reliable measures of muscle strength (16). Published reliability coefficients (r ≥0.90 and ICC ≥0.90) confirm that 1RMs and 3RMs are extremely reliable measures (13,28).
For this study, 15 volunteers participated in the 1RM and 3RM data collection for both the conventional and eccentrically loaded deadlift. During data collection, all 15 participants completed the 3RM testing protocol, however, 2 were unable to complete the 1RM protocol. Data analysis for the 3RM was based off of all 15 participants, but data analysis for the 1RM was only based off of those 13 participants who finished the protocol.
The 15 observations included in the 3RM data analysis yielded a mean 3RM CD of 185.3 ± 16.2 kg and a mean 3RM eccentrically loaded deadlift of 183.8 ± 12.1 kg. The results of a dependent t-test indicated that there was not a significant difference between the 3RM CD and the 3RM eccentrically loaded deadlift (p = 0.30). (Tables 1 and 2).
The 13 observations included in the 1RM data analysis yielded a mean 1RM CD of 203.0 ± 18.5 kg and a mean 1RM eccentrically loaded deadlift of 200.2 ± 19.6 kg. The results of a dependent t-test indicated that there was not a significant difference between the 1RM CD and the 1RM eccentrically loaded deadlift (p = 0.20). (Tables 1 and 2).
For the data collected, a Pearson correlation was calculated to determine the association between and among the modalities. For this section, the conventional deadlift will be referred to as CD and the eccentrically loaded deadlift initiated from the box will be referred to as ED.
For the CD 1RM vs. CD 3RM, there was a Pearson correlation of 0.906 and p ≤ 0.01. For the CD 1RM vs. ED 1RM, there was a Pearson correlation of 0.801 and p ≤ 0.01. For the ED 1RM vs. ED 3RM, there was a Pearson correlation of 0.835 and p ≤ 0.01. For the CD 3RM vs. ED 3RM, there was a Pearson correlation of 0.825, and p ≤ 0.01.
The observed data were also analyzed to determine whether an 1 RM could be estimated from the 3RM using the recommendation of 3RM = 93% of 1RM, as outlined by the NSCA (18). The CD mean estimated 1RM was 199.3 ± 17.4 kg with the actual CD mean 1RM being observed at 203.0 ± 18.5 kg. The Pearson correlation between the 1RM CD estimate and 1RM CD actual was r = 0.91 (p ≤ 0.01). Further, the results of a dependent t-test indicated that the 1RM CD estimate was significantly less than the 1RM CD actual (p = 0.007) (Table 1).
The eccentrically loaded deadlift mean estimated 1RM was 194.5 ± 10.8 kg with the actual eccentrically loaded deadlift mean 1RM observed at 200.2 ± 19.6 kg. The Pearson correlation between the 1RM eccentrically loaded deadlift estimate and 1RM eccentrically loaded deadlift actual was r = 0.84 (p ≤ 0.01). Further, the results of a dependent t-test indicated that the 1RM eccentrically loaded deadlift estimate was nearly significantly less than the 1RM eccentrically loaded deadlift actual (p = 0.061). From a practitioners perspective, p = 0.061 could be arguably considered as clinically relevant (Table 1).
The primary purpose of this study was to determine if an eccentrically loaded deadlift will yield a higher 1RM and 3RM than a CD. Results demonstrated no statistical difference in weight lifted between either deadlift modality; and both deadlift modalities exhibited a high correlation to each other. Although the results did not indicate one modality was superior to the other, one may consider that because of the high correlation of weight lifted between the 2 modalities, interchanging these 2 lifts in a training program may benefit the lifter.
Alternating between the conventional and eccentrically loaded deadlift would create more diversity in exercises and may help to prevent staleness and obtaining the beneficial effects of an additional ground-based compound movement. In this case, 2 similar movements could be variably employed that both demonstrate a segmented action (i.e., 2 distinct movements), consisting of knee and hip extension and an additional trunk extension (8) and cause significant activation of the upper lumbar erector spinae muscles, even more so than the back squat (5,9). When looking at the trained athlete, the use of ground-based, multijoint, free weight exercises such as the deadlift allow for the body to produce a great amount of force, power, and velocity and as a broader ROM, compared with other training modalities (2,8).
Also, heavier loads were pulled by 6 of the 13 participants when initiating the movement from the box and eccentrically loading the deadlift with a countermovement (Table 2). These results indicate for some participants, there may be additional practical benefit to incorporating the eccentrically loaded deadlift into a strength training program; because in theory, if more weight can be pulled through the full ROM using the countermovement, more time is spent under tension at a higher intensity, which equates to a greater total body training stimulus (3,17,30).
In relation to this point, the coefficient of determination (r 2) is a measure of common variance or a measure of common factors of the 2 variables. As already mentioned, the PCC (r) between the 1RMs for the concentric deadlift and eccentrically loaded deadlift was 0.80. Hence, the coefficient of determination is 0.64. In other words, 64% of both the concentric deadlift and eccentrically loaded deadlift come from common factors. This would also indicate that 36% of the concentric deadlift and the eccentrically loaded deadlift come from factors not in common. One could argue that beneficial factors not in common include possible SSC mechanisms such as increased time for force activation (3), preload effects (3), and the recovery of energy stored during the eccentric component of the eccentrically loaded deadlift (3). Incorporating these SSC-related factors in training may have important implications in optimal adaptation and transfer of training to the playing field (1,3,16,17). Additionally, although participants may have failed to lift the weight from the floor after lowering the eccentrically loaded deadlift, they were actually engaging in negatives, which could be used as an effective training stimulus to increase muscle size and strength in a program (21,22).
An observation from this study which is hard to quantify, but may be important for future study, is the technical breakdown in the posterior chain of the eccentrically loaded deadlifts. It was observed that on failed attempts, there was a prominent breakdown in the posterior chain, observed primarily in the rounding of the back. This was not the case for subjects who could pull more with the eccentric DL (i.e., they maintained posterior chain integrity and did not round their back). Posterior chain strength may have been the biggest contributing factor to whether or not the participants pulled a higher load in the eccentrically loaded deadlift compared with the CD.
The secondary purpose of this study was to determine if the 1RM conventional and eccentrically loaded deadlift could be accurately calculated based on the 3RM, where the 3RM reflects 93% of 1RM (18). Although there was a high degree of correlation between the predicted values and the true values, t-tests showed they were still statistically different for both the concentric and eccentrically loaded deadlift. The estimated 1RM was less than the actual 1RM for both the concentric deadlift (p = 0.007) and eccentrically loaded deadlift (assuming p = 0.061 is clinically relevant). This finding emphasizes what many strength coaches already know; percentage relationships across the RM continuum are important for determining optimal load and volume in training progressions; but because of the broad spectrum of athletes, there are no universal conversions that apply across the board.
Much research has been dedicated to finding the optimal percentage prediction chart across the RM continuum, however, results from different research varies greatly among and between exercises and individuals (10,11). For example, highly trained athletes have been shown to perform more repetitions than nontrained athletes at percentage of 1RM (11). These researchers also found a difference in number of repetitions performed between upper and lower body exercises at given percentages of 1RM with lower body movements tending to produce a higher volume of repetitions than intensity guidelines presented by the NSCA (10,11). Because of the great amount of musculature activated during the deadlift (7), it could be argued that the deadlift is, in fact, a total body exercise, recruiting significant lower and upper body musculature. For this reason, additional difficulties exist in establishing deadlift training guidelines at different percentages of 1RM using traditional references, highlighting the importance of actual 1RM testing.
In conclusion, this study found no statistical difference in weight lifted between a CD 1RM and 3RM and an eccentrically loaded deadlift 1RM and 3RM, with a high degree of correlation between the 2 modalities. The results of this study also suggest that 1RM estimates (based on 3RM = 93% of 1RM) are significantly less than actual 1RM measures for the CD and nearly significantly less for the eccentrically loaded deadlift (p = 0.061).
Deadlifts are known to be an optimal lift for developing strength (24). Because of differences between predicted and actual 1RM scores in the deadlift, strength coaches and practitioners should prioritize actual 1RM testing of their athletes and clients to optimize deadlift training loads across the RM continuum. Additionally, this research benefits future deadlift training protocols by establishing that, in theory, conventional and eccentrically loaded deadlifts may be interchangeable within a training program; this may elicit the benefits of using a broader variety of ground-based, multijoint compound movements when training to increase an athlete's total body strength. As the athlete's maximum strength increases, the percentage of 1RM at which peak power occurs also increases (24), an important factor in optimal sports performance.
The authors would like to thank the SUU Athletic Department for use of the Charlie and Renee Norton Strength and Conditioning Center, as well as the SUU football team for allowing the participation of its members for this study. No funding was provided for this study, and the authors have no conflicts of interest related to this research. Results of this study do not constitute endorsement of the product by the authors or the National Strength and Conditioning Association.
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Keywords:Copyright © 2014 by the National Strength & Conditioning Association.
strength training; calculating 1RM; sticking point