Education Resources | Keiser | Engineering Human Performance

How Load-Velocity Profiling Can Optimize Strength and Power Training

Written by Steve Manz | February 24, 2025

Testing a one-repetition maximum (1RM) is a staple in strength training, offering a direct measure of maximal force. But this approach comes with risks. Fatigue, lingering soreness, or poor recovery can affect performance, increasing the chance of injury. Despite these factors, many lifters feel compelled to max out because their program demands it. But is it the best way to assess strength? What if a method existed that provided deeper insights into performance while reducing risk?

One-Repetition Maximum Test Challenges

For decades, strength training programs have used the one-repetition maximum (1RM) test to determine training intensity. This method measures the heaviest load a lifter can move for a single repetition, providing a direct assessment of maximal strength. While effective, the 1RM test has significant limitations.

Injury Risk

First, it carries an inherent risk of injury, particularly for novice lifters, older adults, and those in rehabilitation. Attempting a max lift while fatigued or with improper form increases the chance of strain or injury. This makes it a less-than-ideal testing method for many populations.

Lack of Performance Insights

Second, 1RM testing focuses solely on maximal force output, ignoring other key performance factors such as movement velocity and power generation. It does not assess a lifter’s speed, explosiveness, or ability to produce power under lighter loads—qualities essential not only for athletic performance but also for functional aging and daily movement efficiency.

Variability in Readiness

Fatigue, recovery, nutrition, and mental state can impact performance on test day, making max-out results an unreliable reflection of true strength. On days when readiness is compromised, max testing or training based on a previously recorded 1RM can lead to inaccurate intensity prescriptions and increase the risk of injury.

To reduce risk, practitioners often use submaximal testing protocols, such as estimating 1RM from lighter loads performed to failure. While safer, these methods still emphasize force production alone, without considering speed and power. Moreover, relying on a fixed 1RM can lead to inaccurate training intensities when a lifter’s readiness varies from day to day, increasing the likelihood of overtraining or injury

 

Understanding Load-Velocity Profiling

Load-Velocity Profiling (LVP) provides a safer, more comprehensive alternative to traditional strength assessments. By measuring how movement velocity changes under different loads, LVP not only evaluates strength but also captures key performance attributes like speed and power. This broader insight allows practitioners to fine-tune training intensity, track progress more accurately, and target specific performance qualities beyond maximal strength. LVP enables a more adaptable and individualized approach to training while reducing injury risk.

At its core, LVP examines the relationship between load and movement speed, typically measured in meters per second (m/s). As load increases, movement velocity decreases—an inverse relationship that forms the foundation of Velocity-Based Training (VBT). Unlike traditional percentage-based programming, VBT dynamically adjusts resistance training based on real-time velocity feedback, ensuring workouts align with a lifter’s readiness and goals.

Force-Velocity Profiling vs. Load-Velocity Profiling

Force-Velocity Profiling (FVP) operates on a similar principle but is often considered the gold standard for those with access to advanced data-driven tools. By analyzing force and velocity interactions in greater detail, FVP provides precise performance assessments. However, its reliance on specialized equipment, such as force plates, makes it less practical for many training settings. Additionally, FVP may be more applicable to analyzing jump height versus load while LVP offers a more practical solution for evaluating the relationship between load and velocity in resistance training. 

Accessibility of Load-Velocity Profiling

LVP's accessibility is one of its greatest strengths. With velocity-tracking devices like Keiser’s A400 Technology, practitioners can implement LVP in various training environments without requiring force plates or laboratory conditions. This makes it easier to integrate into daily training while allowing lifters to train on the same equipment used for testing, creating a seamless approach to performance monitoring and optimization. 

Theoretical Variables and Linear Regression in Load-Velocity Profiling

Analyzing human performance through linear regression and parabolic representations provides a detailed evaluation of force and velocity capabilities. These methods help identify key performance variables and asymmetries, offering precise data to guide training interventions. By understanding how force and velocity interact, practitioners can develop more individualized and effective training programs.

 

Linear Regression and Parabolic Representation

Linear regression models the inverse relationship between load and velocity. Data points of force (Newtons) and velocity (meters per second) are plotted, with a linear trend line illustrating performance changes as load increases. The slope of this line provides insight into a lifter’s balance between force and speed. A steeper slope suggests greater force production but limited speed, while a shallower slope indicates higher velocity potential but lower maximal strength.

A parabolic curve represents power output across different loads. Since power is the product of force and velocity, it follows a parabolic pattern—peaking at an optimal load before declining as either force or velocity becomes dominant. This visualization helps identify the load at which a lifter generates maximum power, enabling practitioners to adjust training loads for optimal performance improvements. 

Theoretical Variables in Load-Velocity Profiling

Load-Velocity Profiling relies on several key variables to quantify performance and optimize training strategies. The primary variables include:

  • Vmax (Maximal Velocity): The highest velocity a lifter can achieve with minimal load. This variable reflects speed capacity but may be less reliable at very low resistances.
  • Fmax (Maximal Force): The maximum force a lifter can produce, typically measured at zero velocity. This variable is essential for assessing absolute strength.
  • Pmax (Maximal Power): The peak power output a lifter generates, calculated as the product of force and velocity. This is crucial for movements requiring a balance of strength and speed, making it an important metric for power-focused training. 

By analyzing these variables, practitioners can identify an athlete’s strengths and weaknesses, leading to more precise, individualized training programs that enhance performance outcomes.

 

Procedure for Load-Velocity Profiling

A systematic approach ensures that Load-Velocity Profiling (LVP) produces accurate and actionable results. The key steps include:

  1. Select the Exercise: Choose a foundational lift or specific movement, such as the squat, deadlift, or bench press.
  2. Warm-Up: Ensure the lifter is properly warmed up to prevent injury and collect consistent, reliable data.
  3. Incremental Loading: Start with a light load and progressively increase weight in small increments. Use velocity-tracking equipment to record movement velocity at each load. For larger groups, standardized increments (e.g., 25, 50, 75 lbs) can improve efficiency.
  4. Data Collection: Capture velocity data for each load and plot the load-velocity relationship.
  5. Profile Analysis: Analyze the data to determine individualized training zones and identify optimal load ranges for specific performance goals.
  6. Adjust Training: Use the profile to refine training loads, intensities, and recovery strategies based on real-time data.

Benefits of Load-Velocity Profiling


Unilateral Comparisons

One of the most valuable applications of Load-Velocity Profiling (LVP) is assessing unilateral strength imbalances. By comparing the force and velocity outputs of each limb individually, practitioners can identify asymmetries that may increase injury risk or limit performance. Regular unilateral comparisons enable targeted interventions to correct imbalances and improve outcomes.

Identify imbalances between left and right limbs with Keiser A400 unilateral machines:

  1. Unilateral Range of Motion: See a visual comparison for both left and right sides in both concentric and eccentric phases.
  2. Unilateral Bar Graph: See visual comparisons of power and velocity by rep for both left and right sides. 
  3. Unilateral Resistance Level  

 

 


Rehabilitation and Return-to-Training Protocols

Beyond asymmetry correction, LVP plays a key role in rehabilitation and return-to-training protocols. Lifters recovering from injuries often struggle to regain previous strength and power levels. By incorporating LVP, practitioners can establish baseline profiles pre-injury and monitor these metrics throughout recovery. This approach ensures that strength and power benchmarks are met before returning to full activity, reducing re-injury risk while restoring confidence.

Training Zones

LVP allows for the precise identification of training zones based on an individual’s load-velocity profile:

  • Speed Zone: High-velocity, low-resistance training to develop quickness and explosiveness.
  • Power-Speed Zone: Moderate resistance to enhance overall power with higher velocities (Power = Force × Velocity).
  • Power-Strength Zone: Heavier loads at lower speeds to maximize power output with higher forces.
  • Strength Zone: High-resistance, low-velocity movements focused on maximal strength development.

By programming workouts within these zones, practitioners can tailor training to specific goals, ensuring individuals build the essential attributes needed for performance.

Low-Speed Power and High-Speed Power

A key advantage of LVP is its ability to identify weaknesses along the force-velocity spectrum. LVP data helps determine whether an individual is more force-dominant or velocity-dominant in their power production: 

  • Force-biased power emphasizes strength, requiring the ability to generate force under heavier loads.
  • Velocity-biased power focuses on speed, prioritizing the ability to move lighter loads rapidly. 

 

For force-dominant individuals, incorporating more speed-oriented exercises within the Power-Speed and Speed Zones can enhance velocity-based qualities. Conversely, velocity-dominant individuals benefit from integrating heavier, force-focused movements from the Power-Strength and Strength Zones to improve maximal strength. Tailoring programs in this way ensures balanced development and improved power output. 

Load-Power Profiling with Keiser's A300 Technology

In addition to LVP, Load-Power Profiling (LPP) provides another dimension of performance assessment, particularly when using Keiser’s A300 technology. The A300 machines use pneumatic resistance, allowing for smoother and safer load adjustments, making them ideal for both high-performance training and rehabilitation. LPP focuses on the relationship between load and power output, providing valuable insights into how individuals generate power across different resistances.

While LPP is not as precise as LVP due to the complexity of power being a product of both force and velocity, it still offers significant value. Similar protocols and inferences apply, though power output can fluctuate based on changes in force or velocity, introducing variability in measurements. However, LPP using Keiser’s A300 technology helps practitioners determine optimal loading strategies to maximize power production, bridging the gap between strength and speed. 

Conclusion

Load-Velocity Profiling (LVP) is transforming how practitioners assess and enhance performance. Unlike traditional methods that focus solely on maximal strength, LVP takes a multidimensional approach, incorporating speed, power, and force production. It provides a safer alternative to max testing, delivers more precise intensity prescriptions, and offers actionable insights for injury prevention and performance optimization.

By leveraging LVP for unilateral comparisons, return-to-training assessments, and training zone customization, practitioners can create more effective, individualized programs that maximize results while minimizing risk. Integrating this data-driven approach leads to smarter training, improved performance, and a competitive advantage in any fitness setting.