Chances are you are already familiar with sprint training embedded within long endurance rides. After all, the traditional town sign sprint has been practiced by cyclists for decades.
But what training effects can you expect from this training?
More than being a playful tradition among cyclists, research suggests there may well be valuable performance to gain from structured use of this tradition.
Illustration photo: Duncan Andison / Shutterstock.com
Effects of sprint training in low intensity rides during a 14-day training camp
What happens if you include sprints into low intensity rides during a 14 day training camp?
That is what Almquist and colleagues (1) set out to investigate a few years back. Their results were published in Medicine and Science in Sports and Exercise in 2021. The scientists report on some interesting effects of implementing sprints into low intensity rides.
Their experiment included professional and elite amateur cyclists during a 14-day training camp. 9 male riders (sprint group) implemented sprints into five low intensity rides during the camp. Sprints consisted of four series of 3 x 30 second all-out sprints. Recovery between each sprint in a set were 4 minutes.
A further 9 male riders served as controls (control group) and performed low intensity rides without sprints.
The riders underwent baseline testing 5 days prior to training camp and repeated testing 10 days after the camp. Among several tests were a 60 minute protocol of continuous cycling with four 30-second maximal sprints and a final 5 minute maximal effort.
The results on performance?
The sprint group improved their mean power output for the four sprints with 3%. Whereas the control groups displayed no change in sprint power.
Furthermore, there was a tendency towards the sprint group performing better at 5-minute mean power (p=0.04). However, neither groups achieved a statistically significant change in 5-minute power output. *
* Such a result typically suggests that there may be a trend in favor of the sprint group, but that this finding needs to be interpreted with caution.
Granted, a 3% increase in sprint power is far from mind blowing.
So why should you react with more than a careless shrug of the shoulders? Because there may be more to these sprints than initially meets the eye.
It just so happens that the same group of authors have performed considerable work on the topic of sprint training. Let us have a look at why this matters.
Sprint training in low intensity rides during off-season training
In another paper published in Frontiers in Physiology in 2020, Almquist and colleagues reported on the results of a similar style of sprints embedded in low intensity rides during 3 weeks of off-season training (2).
Again, the participating subjects were male professional and elite amateur cyclists. During a 3-week off-season period riders reduced their training load by approximately 60%. Once a week, 7 riders in the sprint group performed a 90 minute low intensity ride with 3 sets of 3 x 30 second maximal sprints. Again, recovery between sprints within a set were 4 minutes. The remaining training was low intensity only.
A second group of 9 riders served as control and performed low intensity training without sprints.
What happened to performance?
Testing before and after the 3-week off-season period revealed a 4% increase in mean 30-second sprint power in the sprint group. By comparison, mean sprint power decreased by 4% in the control group.
Interestingly, the sprint group had a trend towards better maintaining their mean power (-1%) during a 20-minute maximal effort test. Whereas, the control group displayed a 3% drop in 20-minute power.
Almquist and colleagues observe that the control group displayed a reduction in fractional utilisation of VO2 max [at 4 mmol/L lactate] following the off-season period. Essentially, a reduced ability to consume oxygen.
Fractional utilisation of VO2 max = the percentage of your maximal oxygen uptake you can achieve at a given intensity. The greater this percentage, the greater performance.
The authors suggest that this drop in fractional utilisation of VO2 max is a probably reason for the reduced 20-minute power in the control group.
Which begs the question if sprint training was responsible for preventing a drop in VO2 consumption in the sprint group.
Modest effect sizes, but short interventions
It is worth keeping in mind that the above results were achieved in a very brief time frame.
Specifically, during 3 weeks of training in both studies.
In the great scheme of training adaptation, this is a microscopic duration for progress to occur.
A second point is that the study subjects were very highly trained. As you well know, it is considerably harder for such riders to achieve big leaps in performance, compare to the average amateur racer.
Could we expect greater improvements if training were to continue for longer, or with riders who were below elite level?
The research team of Almquist and colleagues answeres at least one of those questions.
The follow-up to the off-season study
In a follow-up paper authored by Taylor and Almquist they performed and extension of the 3-week off-season experiment. In which they followed 13 of the participants for an additional 6 weeks into their season preparations (3).
At this point, riders commenced their own self-selected season preparations. No sprint training was performed in this 6-week period. Importantly, there were no significant differences in the training between riders from the sprint and control group, which allows for comparing the results between groups.
At the end of the 6-week preparatory period, all riders repeated the test battery from before off-season. Interestingly, the sprint group achieved a mean improvement in 20-minute power of 7% (from 295W avg to 316W avg). Whereas the control group achieved no progress in 20-minute power (from 292W avg to 291W avg).
The authors suggest that this development was likely facilitated by an increase in fractional utilisation of VO2 max. In support of this notion, the sprint group achieved no improvement in VO2 max during this period. Yet, their oxygen consumption during the 20-minute maximal effort test increased by 7%. Which, according to the authors can most likely be explained by greater capacity for consuming oxygen at muscle level.
In line with previous papers on sprint and intensity training
Critics could suggest that a 7% improvement in 20-minute power, induced by three low intensity workouts with sprints only, appears almost too good to be true. Even more so knowing that this change occurred in elite riders.
However, this is not the first study to suggest positive effects of intensity work on maintenance of endurance capacity.
The impact of high intensity work during off-season has previously been investigated by Rønnestad and colleagues (4). They observed that relatively modest amounts of high intensity work during off-season induced down-stream improvements in endurance performance as long as 4 months into preparations for the following season.
One of the interesting new pieces of information from the publications of Almquist, Taylor and colleagues is that such benefits may also be found with sprint training.
Further support for the benefits of sprint training is found in the work of Laursen and colleagues (5). They demonstrated that adding 4 weeks of sprint interval training (at 175% of VO2 max power) to habitual low intensity training resulted in greater 40-minute time trial performance.
Skovgaard and colleagues found that runners who implemented 10 workouts with 30-second all-out sprints over 40 days increased 10-kilometer performance by approximately 3.5% (6).
The notion that sprint training may maintain, and even improve endurance performance during periods of reduced training volume is supported by the findings of additional authors (7-8).
What is the cost of embedding sprints in low intensity rides?
So far we have established that there is a reasonable amount of evidence suggesting sprint training in your low intensity rides may benefit your sprint and endurance performance.
The next obvious question to ask yourself is “at what cost?”
Before adding any training modality to your routine it is worthwhile considering if fatigue from that modality will linger and negatively impact the rest of your training.
Specifically, how will sprint training impact fatigue, recovery and in turn – adaptation from the methods you are already using?
Fortunately, Almquist and colleagues also took an interest in this question. In several of their papers they monitored numerous parameters of fatigue.
Initially, the examined recovery of muscle strength, expressed as knee extension torque following a single low intensity workout with sprints (9). 3 hours after the LIT with sprints exercise, muscle strength was reduced. However, after 24 hours strength was fully recovered.
Furthermore, there was no difference in hormonal stress response between sprint and control groups at the 3 hour point (9).
Put shortly, the elite athletes likely recovered from a single session in 24 hours. Also, including sprints in the LIT ride does not appear to induce any added hormonal stress response.
What about repeated workouts, then?
Almquist and colleagues considered that too. During the 14-day training camp and subsequent 10-day recovery, they monitored stress-recovery state via validated questionnaires as well as perceive exertion after workouts (session RPE) (1).
Interestingly, this revealed no evidence of increased stress or impaired recovery when comparing riders who used sprints with those who did not (1).
Riders in the sprint group rated the initial four LIT with sprint workouts as harder than riders in the LIT group rated their low intensity rides. However, from the fifth LIT with sprint workout, this difference in perceived exertion disappeared.
So it seems that after a brief period of familiarisation, the style of sprinting demonstrated in the work of Almquist and colleagues can be added to low intensity rides without any signs of adverse effects on recovery. At least judging by these results from elite riders.
The take-aways from this post is that embedding sprints into some of your low intensity rides may be a simple and “cheap” investment towards improving your performance.
Specifically, this may contribute towards:
…preventing decline in aerobic capacity during periods of reduced training volume.
…improving performance for durations of 5-20 minute maximal efforts, probably via facilitating greater fractional utilisation of VO2 max.
...improve sprint performance.
If you would like to read more on this topic, the entire doctoral theses of Nicki Windfield Almquist on this subject is available from NTNU’s website.
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- Almquist NW et al. Effects of including sprints in LIT sessions during a 14-d camp on muscle biology and performance measures in elite cyclists. Medicine and Science in Sports and Exercise, 2021;53(11):2333-2345
- Almquist NW et al. Effects of including sprints in one weekly low-intensity training session during the transition period of elite cyclists. Frontiers in Physiology, 2020;11:1000
- Taylor M et al. The inclusion of sprints in low-intensity sessions during the transition period of elite cyclists improves endurance performance 6 weeks into the subsequent preparatory period. International Journal of Sports Physiology and Performance, 2021;16:1502-1509
- Rønnestad BR et al. HIT maintains performance during the transition period and improves next season performance in well-trained cyclists. European Journal of Applied Physiology, 2014;114:1831-1839
- Laursen P et al. Interval training program optimization in highly trained endurance cyclists. Medicine and Science in Sports and Exercise, 2002;34(11):1801-1807
- Skovgaard C and Almquist NW. The effect of repeated periods of speed endurance training on performance, running economy and muscle adaptations. Scandinavian Journal of Medicine and Science in Sports, 2017;28(2):381-390
- Iaia FM et al. Four weeks of speed endurance training reduces energy expenditure during exercise and maintains muscle oxidative capacity despite a reduction in training volume. Journal of Applied Physiology, 2009;106(1);73-80
- Bangsbo J et al. Reduced volume and increased training intensity elevate muscle Na+-K+ pump a2-subunit expression as well as short- and long-term work capacity in humans. Journal of Applied Physiology, 2009;107(6):1771-1780
- Almquist NW et al. Effects of including sprints during prolonged cycling on hormonal and muscular responses and recovery in elite cyclists. Scandinavian Journal of Medicine & Science in Sports, 2021;31(3):529-541