Most of this blogpost is based on below study by Weakley et al. 2021. See all the references at the end of this article.

 

Introduction

Athletes perform resistance training to develop strength, power, and lean body mass. To achieve this, the athlete or their coaches typically prescribe specific resistance training loads relative (%) to an individual’s maximal ability repetition maximum [1RM] based on the desired training goal. However, using an athlete’s previous maximal ability to prescribe training loads can be problematic if the athlete’s 1RM changes as a consequence of training because the prescribed load may not match the % of 1RM intended for the particular session or over a given period. 

What is  repetition maximum (RM)

In 1945 Thomas Delorme described progressive overload for rehabilitated soldiers after World War II. The concept was when the 10 RM was determined, the increase in weight continued until 1 RM was found. For the following week the training load was 10 RM for 7-10 set (70-100 repetitions) for 5 days with 2 days off. After one week a new 10 RM and 1 RM was determined. 

However, more recently, the notion of using training velocity to achieve specific performance goals has been gaining popularity in strength and conditioning training facilities and in the scientific literature (1)

 

WHAT IS VELOCITY-BASED TRAINING AND WHY SHOULD IT BE USED?

Autoregulatory

VBT is a form of autoregulation of training, where day-to-day fluctuations in performance can be accounted for by adjusting the training load. However VBT, is not the only autoregulatory training method, rating of perceived exertion (RPE)  and repetition in reserve (RIR) is properly the most known and used method for autoregulation for strength training and described by a coach and practitioner. However, the RPE and methods require the user to wait until a training set has been performed before any adjustments can be made. VBT can provide real time feedback during the set. There is a near-perfect linear relationship between mean velocity and %1RM.

Daily fluctuations

It is known that the number of repetitions that can be performed with a given % of 1RM may induce different levels of effort and fatigue, therefore, VBT can also help identify proper training loads when fluctuations in performance occur as a result of physical stressors or life stressor, as accumulation stress can result in a decrease in performance. Stress is a condition with specific outcomes from nonspecific inputs, and VBT provides an option for the S&C coaches to select the proper loads in an attempt to prevent nonfunctional overreaching that potentially lead to decrease in performance or an increase in injury. As the mean velocity is a very stable metric and that there is a high positive correlation between the mean velocity of the barbell and % of 1RM, then mean velocity should remain quite stable even though the 1RM may fluctuate over time (1). Research has shown that day to day fluctuation ranged from 6-18% compared with a previously established 1RM. For example those athletes who were prescribed a load of 70% of 1RM for training may in actuality be lifting in a range of 52%–88% of 1RM. By using VBT to account for the daily variability in 1RM, theoretically it should be easier to hit the training target (1). 

See a example in above table from (4)

Specificity of training

With VBT the purpose is to track any submaximal % of 1RM by the athlete moving the barbell as fast as possible, however slower velocity can also be used to get a specific outcome. Theoretically, If athlete A moves the bar slowly and easily at a given intensity, the adaptation may resemble muscle hypertrophy and increase in muscle strength. If athlete B moves the bar as fast as possible at the same relative intensity, improvements in muscle strength and power will be much greater, however, the adaptations of hypertrophy are not well known. Thus, controlling the velocity of load allows the coach to develop the desired training outcome by adjusting the load after the velocity. Researchers have shown that lower-body movements, such as the back squat, tend to have a 100% 1RM moving at a velocity of approximately 0.3 m/s and upper-body movements, which have a shorter range of motion, tend to have a 100% 1RM moving at a velocity of approximately 0.15 m/s (1).

Based on observation, experience, and existing research, these authors (1) believe that many coaches employ loads that are either too heavy or bar velocities that are too slow to maximize training effects. For example when the velocity of hang cleans was measured by attaching the linear position transducer to the bar, the authors found the mean velocity of the bar was between 0.6 and 0.8 m/s, far below the recommended 1.4 m/s velocity for this lift. Once this minimum velocity for the hang clean was achieved, a strong relationship between the lift and vertical jump was observed.

Improving results because of immediately feedback

Study by Randell (2) studied two groups of athletes participating in jump squats, one of which received velocity feedback at each session while the other received no feedback at all. The velocity feedback group significantly improved their jumping and sprinting ability over the non-feedback group. Same result was found by Keller et al. (7) who found better short-term and long-term effect of augmented feedback.

Individualized L-V profile

Another key aspect of VBT is to create L-V profiles to differentiate between normal variation in velocity.

There are two ways for the development of an individualized L-V profile (3)

1. 3 repetitions with 20, 40, and 60%, and 1 repetition with 80 and 90% 1RM, with sets performed 2 minutes apart  
2. A “2- point method” with repetitions performed at 2 approximate loads of 45% of 1RM and 85% of 1RM (3).

It was observed that profiles created from two loads can be as reliable as those created from six loads, as long as the loads used are properly selected. It seems that a light load (about 40% 1RM) and a heavy load (about 80% 1RM) are the best options. However, if one of the two loads are not properly performed (if the athletes are not applying their maximal intended velocity), the results can be drastically altered. Therefore, we recommend performing between 4 and 6 sets with incremental loads to guarantee that the results are reliable.

Weakley et al (2021) (3) have described the two L-V pofile more in detailed. 

VBT in practice

• Mann et al, 2015 (1), suggest a typical 3-week cycle for an athlete wanting to improve strength or power.
• Weakley et al (2021) (3) shows in figure 9 a 10 week example where 4 weeks are spent in strength endurance zone, 4 weeks in strength zone and 2 weeks in a power tapering zone.
• One practical example was an ACL patient that I used a target velocity. I asked him to add load until a speed of 0.6 ms was reached. He ended up with 80kg. However, he thought he lifted heavy when he lifted 50kg. So the ms helped to motivate the patient to reach the desired target. 

Normative values

Furthermore normative values for different lifts have been demonstrated by both Weakley et al (2021) (3) and Balsalobre-Fernández et al (2021) (4).

Although normative values can be used as quick way to estimate % of RM, Ormsbee et al showed that stronger, more experienced bench pressers have slower velocities at 100% 1RM which is probably due to their enhanced technical abilities with maximum weights and possibly a greater mental drive to maximal effort lifting. For example if a Athlete can squat over 1.6 x BWT tend to 1RM with a velocity of < 0.24 m/s a weaker squatter tends to 1RM at a velocity in the range of 0.30-0.40 m/s mark. However, the velocity scores at lighter %1RM (<80%1RM) may be similar. This was confirmed by the work of Helms et al. who found that average velocity scores best predict an athlete’s change in strength when the resistance used are > 80% of 1RM. Basically stronger squatters know how to “grind out” a maximum squat and therefore their 1RM velocities are lower. So to create an Individualized L-V profile no need to exceed the recommended 80% of RM.

When working with Force Velocity training I liked to use above tables and thinking of it as a linear relations and not a curve relationship. I also not use the velocity zone to explains my desired goal, but using basic science understanding from 1RM concept that you have to train at least 70% of 1RM to train strength. Then there is different desired target like strength, power, hypertrophy, muscle endurance.

Other thoughts:

• A hypothetical / anecdote can also be that the average lifter may start to change / compromise their lifting technique when more than 80% of RM is reached. 
• Furthermore, we can also consider finding relevant unilateral exercises that we can measure. For example weighted step ups or single leg squats in a smith machine.

Meaningful change in velocity and smallest detectable difference

In terms of meaningful changes in velocity, the smallest detectable difference in Mean velocity, Peak Velocity, and Mean Propulsive velocity for back squat has been reported to be +-0.06–0.08 m-s, +-0.11-0.19 m-s and 0.08–0.11 m-s, respectively. This suggests that if valid velocity measuring devices are used for monitoring, meaningful changes in velocity between training sessions are likely to reflect acute fatigue or gains in strength. Furthermore, it may also allow for the accurate prescription of resistance training load during training and across mesocycles (3).

Changes of ~ 0.04 m/s from the usual, best velocity scores with a given resistance > 80% 1RM usually indicates a change in 1RM strength by 2-2.5% of 1RM.

Reliability 

Jidovtseff et al (2011) (5) looked at the reliability from three different bench press studies (see figure 2). González-Badillo and Sánchez-Medina (2011) (6) showed in 130 strength-trained males that even though strength increases over 6 weeks mean propulsive velocity (MPV) did not increase (figure 1). A close relationship between mean propulsive velocity (MPV) and % of 1RM was observed (R 2 = 0.98). Despite a mean increase of 9.3 % in 1RM from Test 1 to Test 2, MPV for each % of 1RM remained stable. Stability in the load-velocity relationship was also confirmed regardless of individual relative strength. These results confirm an inextricable relationship between relative load and MPV in the Bench Press which means that 1) evaluate maximal strength without the need to perform a 1RM test, or test of maximum number of repetitions to failure, 2) determine the % of 1RM that is being used as soon as the first repetition with any given load is performed 3) prescribe and monitor training load according to velocity, instead of percentages of 1RM or failure to RM.

Loss of Velocity

In a study by Gonzales-Badillo et al. (2016) (8) looked at the relationship between velocity, effort, and fatigue, and the consequent training adaptations and time course of recovery from fatiguing and less-fatiguing workouts. The study investigated the effects of performing 3 set x 4 reps at 80% of 1RM with no more than a 20% velocity loss versus 3 set x 8 reps at 80% of 1RM with no more than 40% velocity loss for squats. The results were that jumping capabilities of the athletes performing the 3 x 4 workout were recovered within 6 to 24 hours. The results for the 3 x 8 group were not fully recovered at the 48-hour mark. This indicates that higher reps and large decreases in velocity within a set result in large increases in lactate and ammonia and makes it more difficult to recover from the resistance training session. However, all the studies on biomarkers talk about a delay in recovery in relationship to performance, and how it may interfere with other training sessions. So this is properly more related to in-season strength training where strength has to be planned in relation to matches and threshold of velocity loss during sets of squats can be set to 20% and 30% for upper body exercises. However, velocity loss within a set has less clinical meaning in rehabilitation or for the everyday lifter. HoweverSo to limit muscle damage and improve recovery while maintaining strength & power, limit velocity loss during sets of squats to 20% and 30% for upper body exercises.

 

Picture taken from Dr. Dan Baker practical applications part 3 (9)

 

Limitations of VBT

There are several limitations of VBT. 

1. The expense of the technology to assess velocity may make it impractical for some although the prices are getting relatively lower. Check out Pushband, Vitruve, GymAware which are the ones I have experience with. 
2. VBT requires trust between athlete and coach as the coach must trust the athlete is giving their maximal effort on each set of exercises to determine the individualised force velocity curve. However, feedback may increase the autonomy for the athlete.
3. Tracking of the data may be time consuming as well as setting up your training in a standardized way. 
4. The relationship between the mean velocity recorded during a single repetition and the % of 1RM may be influenced by the type of exercise (e.g., squat versus leg press), execution technique (e.g., concentric-only vs. eccentric-concentric), sex (higher values for men at lower %1RM), and the different reliability measurement from devices.

Conclusion

1.VBT can be a valuable addition to quantifying our training or rehabilitation by either lifting slightly faster with the same weight or lifting heavier loads at the same velocity. Ideally you do both.

2.VBT can help identify proper training loads when day to day fluctuations occur as a result of physical and life stressors and thereby minimize the decrease in performance or the risk of injury by adjusting for the target optimal loading.

3.VBT helps identify optimal velocities and specific loads at which to train to enhance specificity of training.

4.VBT provides immediate feedback that can play a role in motivation to get the athletes excited and engage which can lead to improved performance. This can be by trying to lift faster than a former version of yourself: Beat your last session or for the last couple of months.

5.By introducing VBT we can emphasize the “Train smarter, not harder” with live feedback instead of relying on experience and observation.

6.VBT can lift the efficiency of training by tracking daily/weekly changes in strength, power and speed with real-time objective feedback directly to our phones where the data can be logged. Using data to track athletes over time and give information to the athlete and coaches.

Terminology

VBT = Velocity based training

RM = repetition maximum

Average velocity = the velocity score across the entire concentric or “upwards” portion of the lift and this has most relevance to typical “strength” exercises like squats, bench press, and other pressing exercises, deadlifts, pull-ups, rows, and so on.

Peak velocity = the highest velocity recorded in any small portion (eg. 5-msec) of the upwards portion of the lift and this has more relevance to “power” exercises.

Load = weight on the bar 

Reference

1. Mann, J. B., Ivey, P. A., & Sayers, S. P. (2015). Velocity-Based Training in Football. Strength and Conditioning Journal, 37(6), 52–57. doi:10.1519/ssc.00000000000001
2. Randell AD, Cronin JB, Keogh JW, Gill ND, and Pedersen MC. Effect of instantaneous performance feedback during 6 weeks of velocity-based resistance training on sportspecific performance tests. J Strength Cond Res 25: 87–93, 2011.
3. Weakley, Jonathon PhD1,2; Mann, Bryan PhD3; Banyard, Harry PhD4; McLaren, Shaun PhD2,5; Scott, Tannath PhD2,6; Garcia-Ramos, Amador PhD7,8 Velocity-Based Training: From Theory to Application, Strength and Conditioning Journal: April 2021 – Volume 43 – Issue 2 – p 31-49 doi: 10.1519/SSC.0000000000000560
4. Balsalobre-Fernández C, Torres-Ronda L. The Implementation of Velocity-Based Training Paradigm for Team Sports: Framework, Technologies, Practical Recommendations and Challenges. Sports (Basel). 2021;9(4):47. Published 2021 Mar 30. doi:10.3390/sports9040047
5. Jidovtseff B, Harris NK, Crielaard JM, Cronin JB. Using the load-velocity relationship for 1RM prediction. J Strength Cond Res. 2011 Jan;25(1):267-70. doi: 10.1519/JSC.0b013e3181b62c5f
6. González-Badillo JJ, Sánchez-Medina L. Movement velocity as a measure of loading intensity in resistance training. Int J Sports Med. 2010 May;31(5):347-52. doi: 10.1055/s-0030-1248333
7. Keller M, Lauber B, Gehring D, Leukel C, Taube W. Jump performance and augmented feedback: immediate benefits and long-term training effects. Hum Mov Sci. 2014 Aug;36:177-89. doi: 10.1016/j.humov.2014.04.007 
8. Gonzales-Badillo et al. Short-term Recovery Following Resistance Exercise Leading or not to Failure. Int. J Sports Med. 37(4):295-304. 2016.
9. Dr. Dan Baker practical applications part 3: An essential guide to velocity based training
10. Podcast with Matt Jordan https://www.trainwithpush.com/blog/science-of-speed-with-matt-jordan-via-hmmr-media
11. Jovanović, M., & Flanagan, D.E. (2014). From the Field RESEARCHED APPLICATIONS OF VELOCITY BASED STRENGTH TRAINING.