Monday, 28 September 2015

A Different Approach for Endurance Training to Prepare Athletes for Competition: Block vs Traditional Periodization Part 1

A couple of recent studies have looked into Block Periodization (BP) vs Traditional Periodization (TRAD) when it comes to endurance training in well trained endurance athletes (Ronnestad et al., 2014 & 2015). The major physiological determinants of endurance performance are work economy, lactate threshold and VO2max. To improve these 3 qualities, a mixture of low and high intensity training should be performed (e.g. extensive endurance training: 40-120mins @50-60% maximal aerobic speed or 65-75% HRmax; and high intensity training: 4mins @100% MAS). However, it still remains unclear how to organise low intensity training and HIT to achieve optimal performance improvements.

Block periodization (championed by Vladimir Issurin) has been theorised as an effective way to organise endurance training. Block periodization refers to focusing on a few select abilities over a short training block (1-4 weeks) while maintaining other abilities. An example of this would be heavily developing the aerobic system (cardio endurance) while maintaining the alactic system (used for short bursts up to around 10sec). In contrast, traditional periodization looks to develop multiple abilities at once which according to Issurin, leads to suboptimal adaptations in well trained athletes.

In this post, I will just look at Ronnestad et al., (2014) where the authors look to compare a BP model with TRAD periodization in regards to endurance training and leave the 2015 for a separate post. Both papers show similar findings in 2 different endurance athlete populations.

Who were the subjects and how were they grouped?
19 well trained male cyclists were assigned to either the BP or TRAD based on their VO2max. BP cyclists had 6 ± 4 years of competitive experience and had a self-reported 9 ± 3h per week of low intensity training with no HIT in the 2 months lead up prior to this study. TRAD cyclists had 6 ± 4 years of competitive experience and had a self-reported 10 ± 3 per week of low intensity training with no HIT in the 2 months lead up prior to the study.

How was the intervention organised and how long was it?
Both groups performed the same volume of both HIT and low intensity training over the 4 week intervention. Endurance training was divided into 3 HR zones: 1) 60-82%; 2) 83-87%; 3) 88-100% of HRmax. HIT sessions alternated between 6x5 and 5x6mins in the zone 3 intensity with 2.5-3mins rest between intervals. Riders were instructed to perform each HIT session with the aim to produce the highest possible mean power output across the intervals which was used as an indicator of performance. BP group performed a 1 week block of 5 HIT sessions followed by 3 weeks of 1 HIT session with a naturally high volume of low intensity training. TRAD group performed 2 HIT sessions per week throughout the intervention period, interspersed with a relatively high volume of low intensity training.

Illustration of time and volume spent in each zone

What was measured pre, post and during the intervention?
Cyclists reported their perceived well-being in the legs on a 9-point scale, going from very very good to very very heavy after each training week. Pre and post intervention, cyclists performed submaximal and maximal incremental cycling tests to gain; VO2max, Wmax (mean power output during last 2mins of maximal incremental test) and power output at 2mmol/L. There were no significant differences between the groups before the intervention in regards to these variables. I have left a few measures out just to keep this short and less complicated.

What it's like performing the incremental tests

What were the findings?
The BP group significantly increased their VO2max, Wmax and power output at 2mmol/L of blood lactate while no changes occurred in the TRAD group. Wmax increased 2.1 ± 2.8% (P< 0.05) and VO2max by 4.6 ± 3.7% (P< 0.05) with moderate to large effect sizes (ES = 0.85 & 1.34 respectively). Power output at 2mmol/L improved 10 ± 12% (P< 0.05) with a moderate effect size (ES = 0.71). Perceived well-being in the legs was significantly lower in the BP group during the 1st week of intervention compared with TRAD. However, BP reported improved well-being in the legs during the following 3 weeks (P< 0.05).

Summing up
Performing 1 week of 5 HIT sessions followed by 3 weeks of 1 HIT session a week with a general focus on low intensity training resulted in superior adaptations compared with 4 weeks of 2 weekly HIT sessions interspersed with low intensity training. A BP approach could potentially be a better way of preparing for an endurance event than the TRAD approach, especially if preparation time is short.

In the next installment, I will discuss these results a little further and run through some practical applications for sports that are not pure endurance sports such as team and combat sports.


Wednesday, 23 September 2015

Rugby Union vs League. Who’s faster and why?

You may have always wondered which rugby code has the best athletes. Fanatics of each side will always choose their favoured code of the two but now we can take a scientific view. While this won’t give the whole picture as to who are better athletes, we can look into one important facet of performance being speed. With the NRL finals and the Rugby World Cup currently underway, this is a good time to compare both rugby codes.

This recent study by Cross et al., (2015) may give some insight into our question of who’s faster.

NOTE: This data is only a sample of the elite rugby union and league population.

Who were the subjects?

15 elite rugby union and 15 elite rugby league athletes were tested in this study. These were athletes from the New Zealand All Blacks and the New Zealand Warriors NRL squads respectively. Of the Warriors squad; 7 have represented New Zealand, 5 have represented Tonga, 1 has represented Australia, 1 has represented the Cook Islands and 1 has represented Samoa. Hence both groups of union and league athletes being classed as elite.

What was measured and how?

Forwards performed 20m sprints while backs performed 30m sprints. Athlete characteristics (age, height, mass) were recorded between forwards and backs. Sprinting data was collected through a radar gun system (similar to a police speed gun). From the radar system, the authors were able to measure; Vmax (max velocity), v0 (theoretical maximum velocity), vopt (velocity at peak power production), relative Pmax (peak power relative to body mass), relative F0 (theoretical maximum force relative to body mass) and relative Fopt (force at peak power relative to body mass). In addition to this, split times were able to be measured and were at 2, 5, 10, 20 and 30m splits. Some of these variables are explained in my overshoot phenomenon series HERE.

So what were the results?

The only difference in anthropometry was rugby union forwards being moderately heavier than their league counterparts (ES = 1.01). Differences in split times between rugby codes for forwards were unclear for all distances, however rugby union backs demonstrated moderately faster times at all split distances compared to league backs (2m; ES = 0.95, 5m; ES = 0.86. 10m; ES = 0.76, 20m; ES = 0.76, 30m; ES = 0.63). Distance covered by rugby union backs at 2 seconds (ES = 0.75) and 4 seconds (ES = 0.70) was moderately greater than their league counterparts. In addition, rugby union backs displayed moderately greater relative horizontal force (F0), power (Pmax) and greater force produced at peak power (Fopt). Differences in velocity were unclear.

What can we take from these findings?

The most interesting finding in my opinion is that while forwards between codes displayed unclear differences in all of the variables above, they were on average 7.5kg (6.7%) heavier than rugby league forwards. This means that union forwards are able to accelerate and reach velocities similar to league forwards while producing higher amounts of force (ES = 0.77) due to their greater body mass. Effectively, forwards are able to generate greater momentum (momentum = mass x velocity) than league forwards essentially giving them greater ability to break tackles. The authors attributed this difference to the positional demands of rugby union forwards as they have to overcome a greater number of high force movements such as scrums, rucks and mauls which favour athletes who can effectively accelerate their own body mass.

The authors looked further into the acceleration differences between backs. They determined that the increased acceleration seen by union backs would mean at 2sec and 4sec of the sprint they would possibly be 0.44m and 0.73m ahead of their league counterparts respectively. The authors further ascertain that short sprint performance in elite rugby appears to be related to horizontal force and power and speculate that acceleration capabilities would benefit from a more force dominant force/velocity profile.

Rugby Union wins this one

Based on the data presented in this study by Cross et al., (2015), rugby union backs are faster over 30m than their league counterparts. Furthermore, while there were no differences between forwards in short sprint performance, union forwards were 6.7% heavier allowing them to possess greater momentum. A force dominant force/velocity profile seems to be advantageous to short sprint performance (i.e. being really strong in the horizontal direction). This post HERE will give you some ideas on exercises to improve short sprint performance.