Why do we pause to pull?

*** Aaron Kleinwolterink C.S.C.S.

Overview

The National Strength and Conditioning Association defines the Stretch Shorting Cycle as a movement that is initiated from a static position, then beings with a countermovement in which the involved muscles are rapidly and forcibly lengthened, or stretch-loaded, and immediately shortened in a reactive or spring like manner. This stretch shortening cycle is used in most athletic movements. The question is how do you maximize the stretch shorting cycle’s response without injuring an athlete through training? The purpose of this research is to determine if a pause to pull will help maximize the use of the stretch shorting cycle later on in training. Or is the pause to pull not necessary in an athletes training progression

Methods

Pilot work found that subjects who use stretch shorting cycle effectively showed greater gains in vertical jump, long jump, triple jump and overall power production in a hip extension movement.

Experimental Design

Subjects in the experimental group participated in triple extension lifts with the opportunity to use the stretch shortening cycle for the complete study (6 wks). They were taught how to properly perform an aggressive dip and extend to activate the stretch shortening cycle. The Control group performed a pause to extend during the complete study (6 wks). The though behind this was to strengthen their core and set them up to use the stretch shorting cycle later on in the training progression.

Subjects

The study was comprised of high school softball players who were placed in the SSC group and high school soccer players who were placed in the PE group. All subjects where previously trained in some sort of hip extension movement prior to the study. The average age of the subjects was 17 yrs ( +1 yrs), the average height was 68 inches ( + 2 inches), and the average weight was 141.5 ( + 11.65 inches).

Testing and Measurement

Vertical Jump (SVJ):

After a 45 minute warm-up consisting of muscle activation, dynamic flexibility, stability, balance and agility based movements, each subject was given 3 to 4 attempts in a jump and reach ( counter movement jump with no step) using a Vertic device. The best jump was recorded

Long Jump (SLJ):

Each subject was instructed to start with their toes behind the line and jump out as far as possible. Distance was measured with a tape measure from the edge of the line to the back of their heel (closest distance to the start line). They were given 3 attempts and the best of the 3 was recorded.

Triple jump (STJ):

Each subject was instructed to start with their toes behind the line and jump three times continuously as far as possible. Distance was measured with a tape measure from the edge of the line to the back of their heel (closest distance to the start line). They were given 3 attempts and the best of the 3 was recorded.

Tendo Unit lifts (TUL):

Each subject had a cord attached to their bar when performing any triple extension lifts that required a barbell. The cord was then connected to a Tendo Unit which measured the velocity of the bar and the force production produced by each repetition. The best set was recorded from each subject’s workout.

Lower Back Pain Scale (LBP):

Each subject was asked to record after each workout a number from 0 to 3 explaining their lower back pain after the workout. 0- no back pain what so ever, 1- slight back pain during the lift but went away immediately after the lift was completed, 2 – back pain was still significant after the lift was completed, and 3- the subject was unable to finish the workout.

Testing Procedure:

Each subject was pre tested in the previous events the first week of the winter training session( 11/14/05) and was given a post test 6 weeks later ( 12/21/05. Each subject was given proper instruction and was shown proper technique prior to the tests. Subjects were also given 3 to 4 attempts in each test to ensure an accurate test.

Training programs

The training program was broken up into 6, 15 min blocks: 1-warm up, 2-stablity and increase core temp, 3-Athletic movement/low level ploys/speed/agility, 4-power production, 5-strength training, 6-conditioning and core work. The (PE) group performed pause to extension based movements during the power production segment, while the (SSC) croup was allowed to use the stretch shorting cycle. All other aspects of the program remained the same.

• Warm up: primarily composed of muscle activation and dynamic flexibility.
• Stability/ increase core temp: composed of stability ball work for the core and numerous medicine ball activities to increase the core temperature
• Plyo/speed/agility: rapid and short response (basic) plyometeric drills, rhythm and coordination footwork, single cut lateral agility drills, and sprint work.
• Power production: basic hip extension movements such as high pulls, high pull snatch and squat raise to armpit.
• Strength: basic upper and lower body exercises ( squat, lunge, incline press, bent over row)
• Conditioning and core work: medicine ball core circuits combined with stair sprints to get the heart rate up over a ten minute period.

During the power production phase both groups where asked to perform 4 sets of 6 high pulls in which they were hooked up to a Tendo unit. Each subject was then asked to record her best weight, velocity, and power output of each set The (SSC) group was instructed on how to perform the aggressive dip and extend to activate the stretch shorting cycle and were allowed to use it in all of there lifts. The (PE) group was instructed to pause at mid thigh, prior to extending upward and pulling to finish the movement. Both groups were instructed to add weight in increments of 5 lbs only if they were able to produce a velocity of 6.00 ft per sec or higher during the set.

Statistical Analysis:

After the 6 week study the (PE) group went from an average of 6 feet 4 inches in the long jump to an average of 6 feet 8 inches, an increase of 4 inches. The (PE) group went form an average 17 feet 1inch to an average of 19 feet 6 inches, an increase of 2 feet 1 inch. The (PE) group went from an average of 21 inches ( +2.3) in the standing vertical jump to an average of 22 inches ( +2.3), an average increase of 1 inch. The (PE) group showed a surprising increase in the measure of power production on the Tendo Unit starting with an average weight of 48.3 lbs ( + 4.49) and increasing to an average of 55 lbs ( + 16.7) an increase of 6.7 lbs. Their power in watts started at an average of 639.53 ( + 72.31) and went up to an average of 755.83 ( + 194.78) an increase of 116.3 watts. The average velocity of the bar started at 6.09 ft per sec ( +1.38) and went up to an average of 6.19 ft per sec ( +1.79). This is only an increase of 0.1 ft per sec but the average wt of the bar went up by 6.7 lbs. The (PE) group demonstrated all of these increases and only averaged a 1.25 on the low back pain scale.

The (SSC) group went from an average of 5 feet 10 inches in the long jump to an average of 6 feet 4 inches, an increase of 6 inches. The (SSC) group went from an average of 18 feet 3 inches in the triple jump to an average of 19 feet 8 inches, an increase of 1 foot 5 inches. The (SSC) group went from an average of 20 inches ( +3.2) in the standing vertical jump to an average of 21 inches ( + 3.6), an average increase of 1 inch. The (SSC) group also showed a surprising increase in the measure of power production on the Tendo Unit and that was because it was so small. The average weight started at 55.5 lbs ( + 48.4) and increased to an average of 56.42 lbs ( + 18.9) only an increase of 0.92 lbs. Their power in watts started at an average of 728.04 ( + 110.6) and only went up to an average of 729.71 ( + 110.7) an increase of only 1.31 watts. The average velocity of the bar started at 6.05 ft per sec ( +.36) and went up to an average of 6.07 ft per sec ( +1.83) which is only an increase of 0.02 ft per sec. The (SSC) group showed very little increases in the Tendo unit power production and average a 2. 50 in the low back pain scale.

Results

Both groups showed significant increases in the (SVJ), (SLJ) and the (STJ), however the (PE) group showed a much higher increase in the Tendo unit power production section of this study. The (PE) showed an average increase of 6.7 lbs of weight lifted vs. the (SSC) group that showed only an average increase of 0.92 lbs lifted. The (PE) group also showed a huge increase in their power output in watts increasing by an average of 116.3 watts while the (SSC) group only increased by an average of 1.31 watts. The (SSC) also showed a much higher number on the low back pain.

The problems associated with this study were as follows. The (SSC) group just came off of a 12 week training cycle, while the (PE) just came out of in-season play. This indicates to me that the use of the stretch shorting cycle isn’t as bad as this study makes it out to be, it was just over used in this situation. The (SSC) group had already gone through a peaking phase and was trying to produce the same results that they may have received in that phase. Instead they should have spent at least 3 to 6 weeks in a pause to extension phase to strengthen up the movement and set them up for the use of the stretch shorting cycle later on in the program. The (PE) group which was coming off of in season training showed greater results, but they also had more to gain due to the fact that they hadn’t just gone through an off-season program prior to the start of this study. However I do think that the (PE) group had greater results because the pause to extension method of training strengthens the movement before fully maximizing the stretch shorting cycle thus setting them up for greater improvements over time.

Practical Applications

The idea of the stretch shorting cycle is not new, the questions are: is the risk of back pain worth the reward that it can have on explosive lifts. If there is a pause to pull phase introduced in the stability strength phase there is a good chance that your athletes will have less back pain. The pause to pull phase will also strengthen the actual start position of the lift giving the athlete more confidence in attempting the use of the stretch shorting cycle.

If you have an athlete that is solid in using the stretch shorting cycle then the pause to pull phase my not improve your athletes velocity of the bar while they are in this phase. However the phase may strengthen the actual movement setting the athlete up to maximize his or her use of the stretch shorting cycle in the later part of the training cycle.

We will be using this approach in our upcoming strength and stability phase with our volleyball players combined with an isometric pull. We will be researching the pause to pull combined with an isometric pull to see if strength gains at this particular position could maximize stretch shorting cycle and therefore improve vertical jumps. This approach of training has to do with post activation potentiation which is a type of training that preloads a lift prior to a dynamic movement. The upcoming study will hopefully show that a preload pull or a isometric pull can help increase the use of the stretch shorting cycle while improving vertical jump.

References

1. Baechle,T and Earle, R. Essentials of strength training and conditioning.

Champaign, IL:Human Kinetics, 2000.