All traditional weightlifting and CrossFit Strength programming rests on a seemingly solid premise: if you know your front squat 1RM, you know that 70% of that value represents a moderate load, 85% is heavy, and 95%+ is close to maximum. This premise is a simplification that completely ignores the variability of daily neurological readiness.
The research by Jiménez-Reyes et al. (2016) in the Journal of Strength and Conditioning Research demonstrated that maximum voluntary strength in trained athletes can vary between 8% and 18% from day to day, even in the absence of changes in training volume or intensity. The variables that explain this variation include:
- Dream: Reducing sleep to 6 hours decreases maximal force production by 4-8% (Reilly & Piercy, 1994)
- Ambient temperature: Optimal neuromuscular performance occurs between 28°C and 32°C muscle temperature. In cold pits in winter (18-20°C), the effective 1RM can be 5-10% lower
- Hydration status: 2% dehydration reduces peak force by approximately 3%
- Psychosocial stress: Chronically elevated cortisol antagonizes maximal force production through inhibition of the mTORC1 pathway
- Morning HRV: An rMSSD below the personal baseline by 15% or more predicts with r=0.72 a suboptimal performance in high intensity exercises
This means that prescribing "3 sets of 3 repetitions at 90% of 1RM" on a day when the athlete's actual 1RM is 12% lower than theoretically implies that he is trying to move 102% of his actual capacity that day. It is not the planned intensity. It is technical failure training disguised as a structured program.
"The problem with fixed 1RM percentages is not the idea itself, but the false assumption that 1RM is a constant. It is not. "It is a daily variable that responds to the state of the nervous system, not just raw muscle strength."
—Dr. Bryan Mann, Applied Velocity Based Training (2016), University of Missouri
The central principle of Velocity-Based Training is that there is a highly reproducible relationship between the relative load (%1RM) and the mean propulsive velocity (MPV) of a given movement. This relationship, documented with correlations of r = 0.97 to 0.99 in back squat (González-Badillo & Sánchez-Medina, 2010), is much more stable between sessions than absolute 1RM.
The reason is intuitive once it is understood: if in a certain state of fatigue your effective 1RM drops by 10%, so does the speed at which you move each load. The percentage relationship between loads is maintained even if the absolute scale varies. If you normally move 100kg at 0.80 m/s (your ~75%1RM) and today that weight comes out at 0.70 m/s, the VBT system is telling you that today your effective 1RM is lower than the one recorded, and that you must adjust the load to maintain the same planned relative stimulus.
Construction of the Individual Load-Speed Profile
The first step to implementing VBT is to build your individual profile. This requires 1-2 testing sessions where you measure the MPV of 4-6 different submaximal loads (e.g., 50%, 60%, 70%, 80%, and 90% of estimated 1RM). With those 4-6 data pairs (load vs. speed), an individual regression line is constructed that will allow you to:
- Estimate your 1RM in real time based on speed at any load
- Detect days of low neurological preparation before starting the session
- Adjust workload automatically for each session based on the current state of the nervous system
The linear encoder (or speed transducer) is connected to the bar and measures the average propulsive speed of each repetition in real time, allowing the load to be adjusted with millimeter precision.
VBT zone MPV Snatch (m/s) MPV Squat (m/s) %1RM Orient. RIR Main Objective Pure Speed >1.60 >1.30 <50% >8 Inter-muscular coordination, technique Strength-Speed 1.20-1.60 1.00-1.30 50-65% 6-8 Explosive power (Snatch, Jerk) Dynamic Force 0.95-1.20 0.75-1.00 65-80% 3-6 Specific strength-hypertrophy High Maximum Force 0.75-0.95 0.50-0.75 80-90% 1-3 Type IIa/IIb engine recruitment Maximum Limit Force 0.55-0.75 0.35-0.50 90-97% 0-1 Neural adaptation, firing efficiency 1RM 0.40-0.55 0.15-0.35 >97% 0 Assessment test only
| VBT zone | MPV Snatch (m/s) | MPV Squat (m/s) | %1RM Orient. | RIR | Main Objective |
|---|---|---|---|---|---|
| Pure Speed | >1.60 | >1.30 | <50% | >8 | Inter-muscular coordination, technique |
| Strength-Speed | 1.20-1.60 | 1.00-1.30 | 50-65% | 6-8 | Explosive power (Snatch, Jerk) |
| Dynamic Force | 0.95-1.20 | 0.75-1.00 | 65-80% | 3-6 | Specific strength-hypertrophy |
| High Maximum Force | 0.75-0.95 | 0.50-0.75 | 80-90% | 1-3 | Type IIa/IIb engine recruitment |
| Maximum Limit Force | 0.55-0.75 | 0.35-0.50 | 90-97% | 0-1 | Neural adaptation, firing efficiency |
| 1RM | 0.40-0.55 | 0.15-0.35 | >97% | 0 | Assessment test only |
One of the most powerful applications of VBT in the context of CrossFit Strength is the monitoring of percentage speed loss within a series. This parameter is directly correlated with accumulated neuromuscular fatigue and with the percentage of repetitions performed with respect to the maximum possible (MNR) in that load.
The formula: VBT Loss % = ((V_first_rep - V_last_rep) / V_first_rep) × 100
VBT Loss Protocols According to Training Objective
⚡ Explosive Power
Maximum VBT Loss: 10%. 30-40% of the possible repetitions are performed. The neural quality of each rep is maximum. Ideal for Snatch, Clean & Jerk and heavy Box Jumps.
💪 Functional Hypertrophy
VBT Loss: 20-25%. Increased metabolic stress and mechanical tension. Suitable for Squat, Military Press and assistance movements where muscle mass is the goal.
🔩Maximum Strength
VBT Loss: 15-20%. Each rep must be executed with maximum intention of speed. The moment in which the intentional speed drops even though the bar moves, stops the series.
🏃Muscle Resistance
VBT Loss: 30-40%. High metabolic fatigue, used in CrossFit Competition peaking to build tolerance to repeated work under fatigue.
The VBT device market has grown exponentially. Here is an honest comparison of the most relevant options for a CrossFit athlete:
| Device | Precision | Price | Latency (Feedback) | Best For |
|---|---|---|---|---|
| GymAware (Kinetic Performance) | ±0.5% | ~€2,000 | <100ms | High performance centers, coaches |
| PUSH Band 2.0 | ±3-5% | ~250€ | ~300ms (Bluetooth) | Individual athletes, pits |
| Vmaxpro (Sensor + App) | ±2% | ~350€ | <200ms | Individual use with app feedback |
| Wimu Pro (IMU) | ±1% | ~€1,500 | <50ms | High performance, team sports |
| RPE-V method (estimation) | ±8-12% | €0 | Immediate | Boxes without budget for devices |
VBT does not require a complete restructuring of your programming. It can be incorporated as an additional layer of information on top of any existing program. Here's how to integrate it into a typical CrossFit week with a strength component:
Example of Strength Week with VBT
- Monday (Snatch + Front Squat): Warm-up with 3 empty bar lifts measuring MPV. If MPV > usual baseline in empty bar → green day, continue with plan. If MPV < baseline -8% → yellow day, reduce planned load by 10%. If MPV < baseline -15% → red day, light technical work.
- Wednesday (Clean & Jerk + Back Squat): VBT Loss control in each series: cut the series when reaching 12% loss in Clean & Jerk, 20% in Squat (greater tolerance for pure strength movements).
- Friday (Military Press + Technical Weightlifting): Power day: works in the MPV zone 1.00-1.30 m/s with maximum loss of 10%. High rep quality, low overall volume.
The VBT is enhanced when the rests between sets are perfectly controlled, since incomplete neuromuscular recovery biases the speed of the first reps of the next set. The timers TITAN RX They allow you to program breaks of exactly 180-240 seconds with an audible alarm and a voice coach that indicates "Series 3, now!" so you don't have to look at your phone between sets of Olympic lifting.
