A study conducted at the University of Jyväskylä compared two-week blocks of low-intensity training and high-intensity interval training in terms of performance and recovery. Both methods can improve the endurance of recreational athletes after as little as two weeks, when the training load is significantly increased compared to what the individual is used to.
The weekly routine of distance runners usually consists of a permanent mix of low-intensity training and moderate-to-high intensity training. Alternatively, it has been suggested that block periodization with a more focused training goal within a single period of time may have benefits.
A recent study examined block periodization with a setting where participants either added the volume of the low-intensity training by 70% or performed 10 sessions of 6 x 3 minutes (5 times/week) during the two-week block. A short block of low- or high-intensity interval training seemed to be an effective method for recreational exercisers.
“Both groups improved their 3000m running performance immediately after the block,” explains doctoral researcher Olli-Pekka Nuuttila of the University of Jyväskylä. “The interval group improved on average for 13 seconds and the low-intensity group for 11 seconds. The same trend was observed after the recovery week:the time of the interval group was on average 19 seconds faster compared to baseline and in the low-intensity group the difference was 17 seconds. No statistically significant differences were observed between the groups.”
When recovery was considered, differences were found in lower limb muscle soreness, which increased at the group level only in the interval group. The change differed from the low-intensity group over the training and recovery weeks. Increased muscle soreness at the end of the block was also associated with a smaller improvement in the walking test. Resting stress hormone norepinephrine concentrations increased after the block in the interval group and remained elevated after the recovery week. The same trend was observed in nighttime heart rate variability, which decreased during the first week of the block compared to the low-intensity group.
“Based on the recovery markers we measured, the interval block seemed more demanding compared to the low-intensity block,” Nuuttila summarizes. “It would therefore be important to ensure adequate recovery, especially after such a period. It is also advisable to monitor the recovery during these types of blocks at least via subjective markers to avoid undue limitations in the recovery state.”
The effectiveness of block periodization protocols has not been studied in detail in recreational athletes. In particular, previous studies have not examined recovery from different perspectives as well as changes in performance during a block with different training goals.
Changes in endurance performance were analyzed by a 3000 m run test and recovery status was monitored with nighttime heart rate recordings and observed recovery scales. In addition, resting hormone concentrations were analyzed from urine and blood samples.
The participants were 20- to 45-year-old men and women (15 per group) who exercised recreationally.
