Sports Med U | Educating Minds, Elevating Potential

Putting “Heavy” into Heavy Slow Resistance

Morrison, S. and Cook, J., 2022. Putting “Heavy” into Heavy Slow Resistance. Sports Medicine, 52(6), pp.1219-1222.

In today’s letter

• How heavy do you need to lift to start adapting tendinopathies

• Rapid Results = Essentially, you want to lift above 70% 1 rep maximum, but you want to be mindful of the tempo of the lifts (no need to lift too slow as this will drop the amount of reps, reducing the volume and hence the intensity, which is necessary to get positive adaptation)

• 3 Reads to check out to further you knowledge about heavy slow resistance training

• Meme of the week: Don’t bother me before I finish these notes 💩 

Aim of study

This article lays out some considerations about tendon loading that will help clinicians improve their exercise prescription

Did you know?

• Progressive loading is a well-documented and highly effective method for managing tendon pain.

• Emphasis on eccentric exercises is unnecessary, as similar outcomes are achieved regardless of contraction type.

• Heavy slow resistance (HSR) is widely accepted for early tendon pain management because it’s a lot easier to control the load and the rate of loading

• Despite not knowing the exact mechanisms of improvement, patient outcomes support the effectiveness of HSR.

Some fundamental programming principles in HSR research needs clarification to align exercise prescriptions with the concept of "Heavy slow resistance".

 Background information

Key parameters in exercise prescription include:

1. The rate of loading

2. Intensity (load as a percentage of maximum)

3. Time under tension

4. Rest between sets

5. Perceived effort

6. Joint positions

7. Muscle lengths during loading

8. Volume-load (load x sets x repetitions)

• INTENSITY and RATE OF LOADING are crucial for addressing tendon issues.

• To alter the mechanical properties of a tendon, sufficient “stress” needs to be applied during exercise.

• Higher intensities, defined by a percentage of one repetition maximum (1RM), are generally effective for inducing tendon changes.

• Research suggests that an intensity threshold of 70% of maximum load ensures adaptations in tendon properties (No matter if its isometric, concentric or eccentric)

• Some studies report effective tendon changes at lower loads (60% RM), while others suggest loads upwards of 90% RM are necessary.

• In clinical settings, prescribing loads of more than 70% RM is a good starting point for tendon adaptation.

• Determining a 1RM in high-performance settings involves progressively lifting heavier loads until a one-rep-max is reached, which 95% of the time you just cant do in a clinical setting (either due to time or because its just silly due to patient presentation)

• Clinically, a 1RM can be estimated by performing sub-maximal loads to the point of failure (e.g., 3RM or 5RM) and calculating the 1RM

Relative sub-maximal lifting capacity

• Individual factors affect the ability to achieve sufficient intensity in HSR training.

• Understanding a person's training background is very important for assessing their Relative Sub-maximal Lifting Capacity (RSLC).

• RSLC varies significantly based on training history, with endurance-trained people completing more repetitions at 70% RM compared to strength-trained people.

• In addition, trained individuals can complete more repetitions at a given percentage of 1RM compared to untrained

• RSLC is important in tendon conditions, as some tendinopathies occur in highly trained people, while others occur in more sedentary populations.

• Variations in RSLC based on training type and status will affect the actual %RM intensity used, even with similar repetition ranges.

• Completing 12 or more repetitions with a given load likely indicates that the load is less than the 70% RM intensity goal for tendon loading.

• Studies on relative sub-maximal load capacity have involved uninjured people, however, tendon symptoms and dysfunction may influence relative intensity

• Tendon pain usually leads to unloading of the affected area, causing people to use movement strategies that decrease tendon load.

• Isolated exercises can control tendon offloading, ensuring the tendon is still loaded (e.g., calf raises or leg extensions).

• Isolated exercises early in rehabilitation require less skill from the person and allows clinicians to apply the correct intensity more easily.

Time Under Tension and Relative Sub-maximal Lifting Capacity

• HSR training focuses on controlling the rate of loading, visualised as the slope of the force-time curve from movement onset to peak force.

• Rapid loading causes the tendon to respond elastically with less strain, leading to different adaptations than slower loading.

• HSR uses a slow lifting tempo to control the rate of force development.

• Total Time Under Tension refers to the time muscles spend under load, determined by repetitions and the speed of each repetition.

• Time Under Tension may result more from the rate of movement during a set rather than being a crucial factor in training effects.

• The duration of each repetition impacts training intensity if the volume remains constant (e.g., lifting the same weight for the same repetitions at different durations).

• Slower repetition speeds (e.g., 4, 8, or 10 seconds) significantly reduce the number of repetitions that can be performed at the same load.

• Wilk et al found that exercise volume was lowest for sets using the slower repetition tempo, showing that even a small change in repetition tempo can significantly reduce the training volume

• Slower repetition speeds significantly reduce RSLC, with the weight lifted dropping below 70% RM by the 6th repetition and tempo maintenance failing by the 4th repetition.

• Slower tempos in equivalent repetition zones decrease the intensity of the load that can be lifted, falling below the 70% RM threshold around six repetitions at a 6-second tempo.

• HSR protocols often use repetition schemes (15/12/10/8) at 6 seconds per rep, which exceed the maximum number likely to be performed at the desired intensity.

• This suggests that the intensity used in these protocols may not be sufficient to elicit the needed adaptations.

Discussion

• Slow tempo can help coach lower lifting rates, but it's important to balance slow lifting velocities with their impact on intensity.

• This is crucial for clinicians using repetition-based goals of more than 6 repetitions with a 6-second per rep tempo.

• Maintaining high intensity doesn't require abandoning slower tempos; it can be achieved through other methods.

• If slow repetition velocity is important, it can be maintained by lowering repetition goals, thereby increasing the intensity.

• Intensity can also be maintained by programming short intra-set rest periods, allowing more volume at a higher load through incomplete recovery between small "micro sets."

• "Micro sets" can be performed with a load of sufficient intensity, such as 85% RM for 3 × 3 reps with 15 seconds rest between each set of three.

• This approach accumulates volume without sacrificing intensity by using strategic rest periods.

Top 3 Resources

To learn about heavy slow resistance

1. Tendon adapation

   https://www.tendinopathyrehab.com/blog/tendinopathy-updates/what-is-the-best-way-to-load-pathological-tendon 

2. Heavy training and speed development

   https://www.sportsmith.co/articles/can-heavy-strength-training-hinder-speed-development/

3. Tendons stiffness & strain rehab (VIDEO)

   https://www.youtube.com/watch?v=Andaa0i0VBQ 

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