Repeated sprint activity

field hockey players can sharpen quickly

Time compression in modern life makes it difficult for the aspiring hockey player to balance work and or study and life stresses. There are now time-friendly protocols such as High Intensity Interval Training (HIIT) available to strength and conditioning coaches when framing exercise intervention strategies. According to Gibala & McGee, (2008) HIIT is a potent time-efficient strategy to induce numerous metabolic adaptations usually associated with traditional endurance training. Their research has shown that a relatively small number of training sessions (around six) of HIIT over a 2 week training period or an equivalent total of only 15 minutes of highly intense exercise, can increase skeletal muscle oxidative capacity and improve endurance performance. Gormley, Swain, HighSpina, Dowling, Kotipalli, &  Gandrakota,(2008) also showed that when the volume of exercise is controlled, higher intensities of exercise are more effective for improving maximal oxygen consumption than lower intensities of exercise in healthy, young adults. Contrary to previously held popular beliefs amongst the wider community,  short-burst, intense exercise activity not only yields high fitness gains  but has also been found to be enjoyable with the bonus of enabling session completion in short times. Bartlett, et al., 2011 studied a group of athletes training using HIIT and moderate intensity continuous running regimes and showed clearly that ratings of perceived enjoyment after exercise were higher following interval running compared with continuous running. (Paton & Hopkins, 2004) concluded that HIIT (along with explosive resistance training) when incorporated into training programs of low intensity produces substantive performance gains. The specific physiological performance parameters that stand to be improved by adopting HIIT into an exercise program include peak maximal oxygen consumption, first and second ventilatory thresholds and anaerobic capacity; (Laursen, Shing, Peake, Coombes, & Jenkins, 2005).  (Macdougall, et al., 1998) demonstrated that after HIIT, significant improvements were seen in supramaximal treadmill run time, repeated sprint performance and maximum oxygen consumption; the proportion of type II muscle fibres increased significantly. These results demonstrate that 6 weeks of short sprint training can improve endurance, sprint and repeated sprint ability in participants.

For field hockey players in particular, the game specific benefits to be accrued by aligning HIIT with the (RSA) base pattern of the sport are significant. Hockey players are required to repeat high intensity sprints in quick succession when playing. If the physiological and metabolic responses of repeated-sprint protocols are to be specific and relevant to field-based team sports, then the sprint and recovery durations should replicate the movement patterns of these sports (Spencer, Bishop, Dawson, & Goodman, 2005). Although the mean recovery time between sprints is approximately two minutes during the game of hockey (i.e. a mean of 30 ± 12 sprints performed during the 70-minute game), nearly 25% of the recovery periods between sprints were of <21 seconds in duration. The definition of a repeated-sprint bout used here by Spencer et al., (2005) was a minimum of three sprints with a mean recovery duration between sprinting of <21 seconds.  The mean number of repeated-sprint bouts reported during the elite field-hockey game was 4 ± 1 and 2.1 and the mean recovery time between sprints was 14.9 ± 5.5 seconds. From the same study, the average maximal sprint duration is 4 seconds. These findings need to be applied to a structured hockey-specific HIIT program designed to improve RSA performance.

Although the generic program shared in this article is limited to a 5 week period, studies completed by Burgomaster, et al., (2008) suggests high-intensity interval training is a time-efficient strategy to increase skeletal-muscle oxidative capacity and induce specific metabolic adaptations during exercise that are comparable to traditional endurance training. This finding is consistent with the work of Hunter, O’Brien, Mooney, Berry, Young & Down (2011), that showed intermittent peak and peak running speeds along with a 300m shuttle performance run improved significantly amongst Australian Rules footballers subjected to a 4 week repeated sprint training program. Along with framing an appropriate duration for any exercise intervention program intended to significantly improve RSA total work output, the fidelity of the prescription is also crucial in optimising performance gains.

Edge, Bishop, Goodman, & Dawson (2005), ran a study with twenty female athletes and assessed pre- and post-training, for maximum oxygen uptake, lactate threshold (LT), and RSA (using a protocol of five repetitions of sex second maximal sprints, every thirty seconds).  Before and immediately after the RSA test, muscle biopsies were taken from the vastus lateralis. Participants were matched on RSA, randomly placed into the HIT group of ten members or moderate intensity continuous training (MIT) group of ten members and completed a five week cycle training program with training sessions held three days per week. They performed either HIT or MIT sessions as part of the program. The researchers found that both groups had significant improvements in oxygen uptake and LT, with no significant differences between them. Both groups also had significant increases in RSA total work but there was a significantly greater increase following HIT than MIT (13 vs 8.5%, respectively; P < 0.05). This suggests, along with the work of Spencer et al., (2005) that any program designed to improve RSA output needs to be based on a tailored HIIT program rather than MIT.

Designed specifically to cater for the  physiological and metabolic responses of  higher grade club level hockey, the intervention program uses repeated-sprint protocols with sprint and recovery durations that aim to replicate the movement burdens of the sport; Spencer, Bishop, Dawson, & Goodman  (2005). This capacity-focused program aims to extend the length of time that the anaerobic alactic system contributes to game related running activity. Although the program is limited to a 5 week period only, studies completed by (Burgomaster, et al., 2008) suggests that high-intensity interval training is a time-efficient strategy to increase skeletal-muscle oxidative capacity and induce specific metabolic adaptations during exercise that are comparable to traditional endurance training.

The participants were restricted to work periods of 10 to 12 seconds maximum, with a rest period set at 6-10 times the duration of the work period to start and slowly moved towards 4 times the work interval by the end of the program. For example, a program session with a 10 second sprint has a rest time of 50-60 seconds, on average; of course these can be tweaked based on whatever RSA-focused standard fitness testing you have employed reveas about fitness levels. Participants are encouraged to complete the interval work so that the pace or power output for each work segment of the interval is consistent.  Once the participants can complete a full training session with less than a 10% speed drop from their first interval to their last interval they are in a better position to cope with a decrease in the rest period. The rest period is generally less than that used in field hockey speed and agility work. The work volume was calibrated according to total work time; a target volume of 4-6 minutes pre-set was accomplished by participants doing several sets of 60s-80s work per set. At the end of each set participants took a 5- 10 minute active recovery break, comprising of a walk or slow jog. A very basic work and recovery guide for the program follows in the table  below.

Table  HIIT-RSA intervention program detail

Week	Session	Work	Rest	Pause
1	1	10 x 8s	60s	6 minutes
		12 x 6s	40s	6 minutes
		8 x 10s	60s	6 minutes
2	1	12 x 5s	40s	6 minutes
		10 x 3s	30s	6 minutes
		8 x 5s	40s	6 minutes
	2	12 x 8s	75s	6 minutes
		12 x 6s	40s	6 minutes
		10 x 8s	70s	6 minutes
3	1	12 x 5s	30s	5 minutes
		12 x 3s	30s	5 minutes
		10 x 5s	40s	5 minutes
		8 x 8s	75s	5 minutes
	2	12 x 8s	60s	5 minutes
		12 x 6s	35s	5 minutes
		12 x 5s	65s	5 minutes
		6 x 129s	75s	5 minutes
4	1	10 x 5s	25s	5 minutes
		10 x 3s	25s	5 minutes
		12 x 5s	30s	5 minutes
		12 x 3s	20s	5 minutes
	2	12 x 8s	60s	5 minutes
		12 x 6s	30s	5 minutes
		12 x 10s	60s	5 minutes
		6 x 12s	65s	5 minutes
5	1	10 x 5s	25s	4 minutes
		10 x 3s	25s	4 minutes
		12 x 5s	30s	4 minutes
		12 x 3s	20s	4 minutes
		10 x 8s	50s	4 minutes
	2	12 x 8s	50s	4 minutes
		12 x 6s	30s	4 minutes
		12 x 10s	50s	4 minutes
		6 x 12s	60s	4 minutes
		8 x 6s	30s	4 minutes

Any intense intervention such as this should be balanced across the periodised programming of the group across the performance year and be mediated by the standardised fitness testing protocols in place.