RESEARCH: Studies shared from 20 to 26 Feb 23

All the studies I've shared are available on the RESOURCES PAGE.

This week's quick summary:

• Individual physiological responses to shoe stiffness
• Return from underperformance to sustainable world-class level
• Percussive massage treatment for range of motion and performance
• Benefits from repeated bout effects of downhill running
• Reducing the peak tibial acceleration by music-based biofeedback

EQUIPMENT: Individual physiological responses to changes in shoe bending stiffness

There appears to be a benefit for highly cushioned and resilient racing shoes for runners at all speeds and Nike Vaporfly shoes appear to work well for interval training. It is the combination of the stiffness and the foam used in the shoe that results in better performance. This study set out to investigate the stiffness of a shoe and its impact on running economy.

STUDY DETAILS

1. Our purpose was to study the runner-specific metabolic responses to changes in shoe bending stiffness.
2. After assessing their maximal oxygen consumption and aerobic speed (MAS) during a first visit, 96 heterogeneous runners performed two treadmill 5 min runs at 75% max with two different prototypes of shoes on a second day.
3. Prototypes differed only by their forefoot bending stiffness (17 N/mm vs. 10.4 N/mm).
4. Considering the whole sample (n = 96), there was no significant difference in RE between the two conditions.
5. Cluster 1 (n = 29) improves RE in the stiffest condition (2.7 ± 2.1%).
6. Cluster 2 (n = 26) impairs RE in the stiffest condition (2.7 ± 1.3%).
7. Cluster 3 (n = 41) demonstrated no change in RE (0.28 ± 0.65%).
8. The present study highlights that the effect of shoe bending stiffness on RE is runner-specific. High-level runners took advantage of increased bending stiffness, whereas medium-level runners did not.

PRACTICAL TAKEAWAY

The benefit for running economy of a stiffer running shoe appears to be variable and depends on the characteristics of the runner. Runners should keep this in mind when selecting a supershoe as different models may provide different benefits depending on how they run. My conclusion from two weeks ago remains the same: "My recommendation is for any runner who wants to perform their best in road running races to find the most comfortable supershoe for them".

PHYSIOLOGY: The return from underperformance to sustainable world-class level

This case study set out to "determine the main factors associated with unexpected underperformance and prospectively describe the holistic process of returning to sustainable world-class level in a male cross-country skier".

STUDY DETAILS

1. Longitudinal training data was retrospectively analyzed across nine seasons (2012-2013 to 2020-2021), and categorized into training forms (endurance, strength, and speed), intensities [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and modes (specific and non-specific).
2. Following two seasons of unexpected underperformance (2019-2020 and 2020-2021), the participant was prospectively followed in the process of returning to sustainable world-class level (2021-2022).
3. Day-to-day training data and physiological tests were analyzed, and interviews with the participant and the head coach conducted.
4. After two seasons of unexpected underperformance with relatively similar training volumes and intensity distributions as in the preceding seasons, the possible contributing factors were identified:
   • lack of training periodization
   • limited monitoring and intensity control
   • an “extreme” regime of training with low carbohydrate availability and days including two MIT sessions
   • lack of systematic technique training and follow-up by coaches on a daily basis
5. Accordingly, the participant’s return to world-class level targeted these possible reasons for underperformance by a clear micro-cycle periodization, more systematic physiological monitoring and testing, optimized CHO intake, as well as increased emphasize on intensity control and technical development through closer follow up during daily training.
6. The holistic approach described in this case study may serve as a theoretical framework for future studies and practical work with underperforming endurance athletes.

PRACTICAL TAKEAWAY

This is a useful case study that provides insight into the training of a world-class athlete. The first takeaway for me is that the training which took the athlete to the world-class level was not the same training he needed later in his career. The second is that managing total training load is important and this was managed through periodization, reducing MIT sessions, and using careful intensity control. Finally, fueling the work required and making sure that the athlete had enough carbohydrate availability was essential.

EQUIPMENT: The acute effects of a percussive massage treatment with a Hypervolt device on plantar flexor muscles’ range of motion and performance

STUDY DETAILS

1. The purpose of this study was to investigate the effects of a 5-min percussion treatment of the calf muscles on range of motion (ROM) and maximum voluntary contraction (MVC) torque of the plantar flexor muscles.
2. Sixteen healthy male volunteers were tested on two separate days with either a 5-min massage treatment of the calf muscles with a Hypervolt device or the control condition (sitting only).
3. Maximum dorsiflexion ROM increased with a large magnitude following the massage treatment by 5.4°, while there was no change in the control group.
4. Moreover, MVC torque did not change following both the massage treatment and the control treatment.
5. Since we found no changes in MVC, we suggest including a percussive massage treatment in a warm-up regimen to optimize the flexibility level of an athlete, without losing muscle performance

PRACTICAL TAKEAWAY

Percussion massage provided a useful range of motion benefit for the athletes without reducing their voluntary contraction torque suggesting that it is a useful application without any performance-decreasing downsides. I would follow the suggestion from the authors and use percussion massage, a 5' treatment, as part of a warm-up routine before an important training session or race.

DOWNHILL: Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running

Running downhills effectively later in a race results in superior performance. The challenge is that running downhill results in significantly higher impact forces, muscle damage, and soreness. Therefore preparing for races with significant downhills is important and this is where the repeated bout effect needs to be considered. This paper "used downhill running as a model to investigate the repeated bout effect (RBE) on neuromuscular performance, running biomechanics, and metabolic cost of running".

STUDY DETAILS

1. Ten healthy recreational male runners performed two 30-min bouts of downhill running (DR1 and DR2) at a –20% slope and 2.8 m/s 3 weeks apart.
2. Neuromuscular fatigue, level running biomechanics during slow and fast running, and running economy parameters were recorded immediately before and after the downhill bouts, and at 24 h, 48 h, 72 h, 96 h, and 168 h thereafter (i.e., follow-up days).
3. An RBE was confirmed by attenuated muscle soreness and serum creatine kinase rise after DR2 compared to DR1.
4. An RBE was also observed in maximum voluntary contraction (MVC) force loss and voluntary activation where DR2 resulted in attenuated MVC force loss and voluntary activation immediately after the run and during follow-up days.
5. This study demonstrated evidence of adaptation in neural drive as well as biomechanical changes with the RBE after DR.
6. It can be concluded that the RBE after downhill running manifests as changes to global and central fatigue parameters and running biomechanics without substantially altering the energy cost of running.

PRACTICAL TAKEAWAY

Even a single dose of downhill running resulted in improvement in subsequent downhill runs. This is encouraging for athletes preparing for downhill races because it means a relatively small dose (only a few runs) can result in a benefit. It appears that the benefits from the repeated bout effect last approximately 6 weeks and a conservative time for recovery after one of these sessions appears to be 3 weeks. Therefore my recommendation is to perform long (+30') downhill runs every 3 weeks with the last session 3 to 4 weeks out from a focus race.

PHYSIOLOGY: Reducing the peak tibial acceleration of running by music-based biofeedback

This is the first time I've seen a study using music as a means of biofeedback for biomechanical retraining.

STUDY DETAILS

1. Twenty runners with high peak tibial acceleration were allocated to either the retraining or control groups.
2. A body-worn system collected axial tibial acceleration and provided real-time feedback.
3. The retraining group received music-based biofeedback in a faded feedback scheme. Pink noise was superimposed on tempo-synchronized music when the peak tibial acceleration was ≥70% of the runner's baseline.
4. The control group received tempo-synchronized music, which acted as a placebo for blinding purposes.
5. A significant group-by-feedback interaction effect was detected for peak tibial acceleration.
6. The experimental group had a decrease in peak tibial acceleration by 25.5% without changing the running cadence.

PRACTICAL TAKEAWAY

I don't know if there is anything practical that we can take away from this study. However, it is very interesting and does present a potential means of training that could reduce injury risk. My takeaway is that I will be open to learning about new technologies that take advantage of music-based biofeedback if I hear of them in the future.