Cycling performance: core training vs. weight training

As any subscriber to SPB will know, the evidence for the role of strength training as a method of improving sports performance is robust and overwhelming. Elite coaches across the world now understand that strength, and its manifestations – power, speed, and muscle economy (how efficiently muscles work) -are more closely related to performance than any other quality. Moreover, the benefits of strength training for endurance athletes have been demonstrated in numerous scientific studies, many of which have been reported in SPB over the years (see this article by Tom Whipple for a comprehensive outline of the benefits of strength training for athletes and the kind of programs that work)^(1-4).

Strength options for cyclists

When it comes specifically to cycling performance, strength training as part of an overall program is no less important if performance really matters. Why does strength training benefit cycling performance? Research has identified a number of physiological mechanisms at play including:

·        Strength training can delay the activation of less efficient type II muscle fibers, improve neuromuscular efficiency, and convert fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, which allows higher workloads to be performed for longer.

·        Strength training can improve muscle-tendinous ‘stiffness’, resulting in more ‘rebound’ and less internal energy losses, which increase muscle economy (the amount of force muscles can generate per unit of oxygen consumed)⁽⁵⁾.

·        Strength training enables muscles to generate more torque (turning force at the crank) for a given level of blood lactate (a marker of muscle fatigue). Once again, this allows muscles to work harder for longer before fatigue intervenes⁽⁶⁾.

However, the use of strength training using heavy weights and conventional exercises such as squats, lunges, leg press etc is not the only type of strength work that is recommended for cyclists. Since road cycling is characterized by performing large training volumes during which a fixed forward-leaning posture is used, a number of coaches and scientists have suggested that training the stabilizing muscles required to hold this posture using a ‘core strength’ program is also beneficial⁽⁷⁾.

The theory is that by targeting the core muscles around the spine that are involved in stabilizing the spine and holding this posture, energy ‘leaks’ are prevented and biomechanical function becomes more efficient. This in turn allows greater force generation in the moving limbs (legs)and better performance (see box 1 for a more detailed explanation of core stability)⁽⁸⁾.

What is core stability?

There are a variety of definitions for the term core stability. One of the best descriptions is summed up by Tracy Ward, a researcher, physiotherapist, author and practitioner of core stability training and is described as “the ability to control the position and motion of the trunk over the pelvis to allow optimum production, transfer, and control of force and motion to the terminal segment in integrated athletic activities”⁽⁹⁾. In short, the core muscles are crucial for controlling spine and trunk function, which then allows you to move as efficiently as possible when transferring the force required from your core to your limbs.

In terms of the muscles involved, the core consists of a group of deep abdominal muscles that surround the trunk. At the front there is the transversus abdominus (TrA) (horizontal around the stomach area), rectus abdominis (in the 6-pack region of the stomach running vertically), and the external and internal obliques cover the sides of the trunk. The core support extends beyond these immediate muscles and also involves the pelvis with iliopsoas running from the spine to the pelvis, and at the back there is the erector spinae muscles that span vertically up the whole spine, multifidus (closer in to the spine) and quadratus lumborum (from the lower spine to the pelvis). When these muscles are activated or contracted, they have a collective response upon each other - ie the activation of one will activate the others and produce a corset of support around the spine. This in turn allows higher loads, and faster transfer of forces from the upper and lower limbs through the core^(10).

Real world data

The research above shows that both strength training and core training result in improvement of various key physiological parameters known to be associated with excellent cycling performance. However, improving key physiological parameters is not the same thing as improving actual performance in real cyclists in real-world conditions. Surprisingly, relatively few studies have been carried out looking at the effects of strength training (of either type) in real-world conditions, which means there’s still a degree of uncertainty regarding the true effect of conventional strength training or core on cycling performance. One reason for this is that few competitive cyclists are willing to forego the potential benefits of strength training over a period of many months in order to provide scientific data for a research project!

In recent years however, research into cycling performance has started to focus on cycling power profile rather than physiological parameters such as lactate thresholds, oxygen uptake (VO2max) and cycling economy. Power profiles are generating increasing interest among scientists because once analyzed, they allow researchers to accurately predict performance. Using the power-profile method allows an accurate, flexible, and inexpensive way tracking of performance over time without resorting to and complicated laboratory testing. Indeed, studies show that maximal power outputs over 5-second, 60-second, 5-minute, and 20-minute intervals can be used to accurately track anaerobic muscle fiber metabolism, maximal oxygen consumption, and maximal sustained performance over time, respectively^(11-13).

Core vs. traditional weight training for cyclists

Given the relative uncertainty the lack of previous studies regarding the real-world benefits of conventional weight training, and the impact of core training on cycling performance in the field, a team of Spanish scientists from the University of Lleida in Catalonia decided to compare these two strength training modes using the technique of power profiling⁽¹⁴⁾. Published in the Journal ‘Cureus’, this study compared the power profile of trained road cyclists after 12 weeks of either conventional strength training or core training or no strength training at all during the preparatory phase of the annual training plan.

What they did

Thirty-six cyclists highly trained cyclists were recruited, all possessing a world tour, elite/U23, masters, or recreational cycling license. The study was set up to run from November to January, encompassed the off-season and the initial phase of preparation leading up to the competitive season – exactly the time when pro cyclists would be undertaking pre-season strength training programs. The 36 cyclists were randomly allocated into one of three groups:

·        Cycling only – the cyclists in this group simply maintained their cycling training program for the 12-week intervention period.

·        Cycling + core training – the cyclists in this group trained on the bike as above, but also performed a core strength program during the intervention period.

·        Cycling + traditional strength training - the cyclists in this group trained on the bike as above, but also performed a traditional weights program during the intervention period.

Immediately before and again after the 12-week intervention period, all the cyclists underwent power profiling using a laboratory calibrated stationary bike. This bike was fitted with Favero Assioma pedals, which were able to accurately record the cyclists’ power outputs during the profiling procedure. The power profiling procedure itself was based on recognized and validated protocol developed by Allen et al⁽¹⁵⁾. Included in this protocol are warm up and recovery segments to ensure cyclists can perform to their maximum ability. This protocol consisted of the following (actual power measurement segments are shown in bold):

A) 20 minutes at a self-selected easy intensity.

B) Three 1-minute fast pedaling accelerations (100-105 rpm) with a 1-minute recovery between efforts.

C) Five minutes at a self-selected easy intensity.

D) One all-out 5-second sprint.

E) Five minutes at a self-selected easy intensity.

F) 1-minute all-out effort.

G) Five minutes at a self-selected easy intensity.

H) 5-minute all-out effort.

I) Ten minutes at a self-selected easy intensity and five minutes of resting.

J) The main part of the test - consisting of a 20-minute maximal effort, where subjects were asked to produce the highest mean power output possible for this duration and adopt their personal pacing strategies.

During the protocol, the cyclists could view their progress on a computer monitor, and were provided with information regarding time to completion and gear choice. Maximal sustained power outputs across each selected duration (in bold) were recorded in terms of watts per kilo of bodyweight (a fundamental parameter for measuring cycling performance – see this article). The cyclists’ maximal oxygen consumption values were also estimated using a formula based on relative power output obtained during a 5-minute interval⁽¹⁶⁾.