The Need for Off-Season Non-Specific Conditioning

In this article, guest writer and Firstbeat client Konstantinos Stratakis discusses the role of off-season conditioning in team sports, including balancing sports-specific and non-specific conditioning like HIIT. He also explores how Firstbeat supports off-season training by providing insights into internal and external training loads, aerobic and anaerobic effects, and athlete readiness.

Konstantinos is a certified performance and sports scientist, as well as a strength and conditioning specialist. He is currently pursuing a PhD in Sports Medicine. Throughout his career, he has worked as a strength and conditioning coach in various sports, including basketball, water polo, and volleyball.

The Importance of Off-Season Training

An athlete’s annual training plan includes different periods or seasons, each with distinct training goals, performance outcomes, and demands. The off-season is a critical period as it focuses on developing the physiological, psychological, and technical foundation from which peak performance is developed during the in-season. Without an appropriate exposure to training load during the off-season, an athlete’s ability to enhance performance and reduce the risk of injury during the in-season will be hindered.

In the early part of the off-season, athletes undergo lower training loads and focus on general training to improve overall fitness. As they progress through this phase of the annual training plan, their workload (both in terms of volume and intensity) gradually increases as their work capacity improves and training becomes more specific. This helps them move towards achieving the required sporting form and level of preparedness needed for competitive success.

Several key factors should be considered to determine the specific off-season training targets and guide the athlete’s sporting form. These factors include evaluating time availability, the athlete’s past competitive performances, conducting performance testing, forecasting performance needs for the upcoming season, and performing physical assessments and medical screenings.

It’s important to note that training during different periods or seasons should be approached comprehensively. Training decisions should be based on a well-designed monitoring program that assesses the athlete’s psychological and physiological responses (internal training load) to the training program (external training load) while considering the targeted training outcomes.

While the application of different strength and power methods and modalities during the off-season has received a lot of attention, less focus has been placed on the periodization and programming of non-specific metabolic conditioning during the period of the annual plan.

Most athletes aim to maintain or develop their metabolic conditioning during the off-season by engaging in individual skills training and small-sided games (SSGs). While all metabolic conditioning ideally should be done through playing and practicing the sport, as it’s challenging to replicate the physical and emotional stress produced by the sport, it’s crucial to recognize the potential drawbacks of SSGs and individual skills work as a tool for improving metabolic such as:

• Difficulty in controlling work intensity
• Challenges in organizing the training structure
• Increased risk of contact and/or overuse injuries
• Technical ability required
• Need for availability of resources
• Possible ceiling effect

Non-specific conditioning methods do not substitute for small-sided games (SSGs) and individual skills work but rather complement them as individualized tools that provide a controlled environment for developing metabolic conditioning while objectively measuring progress.

It is worth noting that different conditioning methods fall across the intensity spectrum from low to high, depending on the overall load on the body. When intensity is lower, more volume is generally needed to achieve training adaptations and improve conditioning. While there are various methods of metabolic conditioning, discussing and analyzing each one is beyond the scope of this article. This article is about understanding the role of High-Intensity Interval Training (HIIT) as a non-specific conditioning method in the off-season.

Small-sided game (SSG) in football.

HIIT Training – What? Why? How?

HIIT training is defined as the repeated performance of relatively short intervals of high-intensity work interspersed with low-intensity work or rest intervals, where full recovery is usually not allowed. HIIT has gained popularity due to its ability to positively impact both the aerobic and anaerobic systems while inducing neuromuscular adaptations in a time-efficient manner.

Nine HIIT variables, including work intensity, work duration, recovery interval intensity, recovery interval duration, exercise modality, number of intervals, number of series, between-series recovery duration, and between-series recovery intensity, can all be manipulated to modify the physiological load (aerobic, anaerobic, neuromuscular).

In HIIT, there are two types of indicators for load intensity: external and internal. External indicators include running speed at VO2max (vVO2max or MAS), maximum sprinting speed (MSS), anaerobic speed reserve (ASR), and VIFT (achieved speed in the intermittent fitness test 30-15) for running, as well as power output at VO2max (PVO2max) and maximum power output (Pmax) for rowing and cycling. On the other hand, commonly used internal intensity indicators include heart rate (% of HRmax), level of perceived exertion (RPE), and blood lactate accumulation.

According to the authors of the book “Science and Application of High-Intensity Interval Training,”  there are four HIIT formats:

When using different HIIT formats, it’s essential to consider the specificity continuum of exercise modalities. More specific exercise modalities, such as patterned running, are great for simulating the demands of the sport. In contrast, more general modalities, like biking, are better for inducing central adaptations without overloading specific structures.

In my practice, during the early off-season, I typically use more general exercise modalities with no emphasis on decision-making. However, as the off-season progresses, I frequently utilize more specific exercise modalities while emphasizing decision-making. I will delve into this further in later sections of this article.

HIIT Training and Aerobic, Anaerobic, and Neuromuscular Contribution

The different formats of High-Intensity Interval Training (HIIT) have distinct effects on the aerobic, anaerobic, and neuromuscular systems. As mentioned earlier in this article, adjusting the nine different HIIT variables can modify the overall physiological load.

Regarding the aerobic contribution during HIIT, both short and long HIIT sessions are effective for accumulating time above 90% of VO2max, which indicates the program’s effectiveness in improving aerobic fitness. For repeated sprint intervals, 4 seconds of work, including jumps and change of direction (COD), and 20 seconds of active rest maximize time above 90% of VO2max, even though it may not be the optimal method for this purpose. Sprint interval training does not maximize time above 90% of VO2max, despite high demand for muscle oxygenation. However, the aerobic system contributes more to energy production with higher session volumes.

Some coaches prefer to limit the anaerobic contribution of specific HIIT sessions to lower the overall Rating of Perceived Exertion (RPE) or avoid depletion of glycogen stores while accumulating higher volumes of near VO2max training.

HIIT long intervals with higher work intensities, longer work intervals, and shorter rest intervals result in a higher rate of blood lactate increase. Active recovery during longer rest intervals can accelerate blood lactate clearance.

Short HIIT sessions with similar mean intensity but higher work interval intensities elicit more significant blood lactate responses. Increases in the work/rest ratio and work interval durations are associated with increases in the initial rate of blood lactate accumulation.

With increased recovery intensities, a progressive increase in blood lactate is observed at exhaustion. The initial rate of blood lactate accumulation during repeated sprint intervals is primarily correlated with the work/rest ratio. Sprints longer than 4 seconds and rest intervals less than 20 seconds elicit more blood lactate accumulation. Greater change of direction (COD) angles may increase muscle recruitment, but absolute sprinting speed is lower, resulting in less lactate accumulation.

In sprint interval training, shorter sprints and/or lower intensities will lower the anaerobic glycolytic energy contribution. Sprints longer than 45 seconds engage a more significant contribution from the aerobic system. For more lactate production, recovery periods should be long enough to allow the aerobic system to return to its resting levels while avoiding over-acidic status.

Managing neuromuscular load during HIIT training is crucial as it affects various aspects such as time at VO2max, potential carry-over effects for subsequent training sessions, long-term neuromuscular adaptations, and injury risk.

During long intervals, the majority of muscle fibers might already be recruited, but the firing rate and relative force development per fiber are likely greater during short intervals. Long and short intervals with more anaerobic contribution might lead to more fatigue. “Bigger” athletes might experience higher musculoskeletal load during long intervals due to poor running economy. Incline running and softer surfaces reduce neuromuscular strain during short and long HIIT intervals.

A higher work/rest ratio is generally associated with a more significant impairment of repeated sprinting capacity during sprint interval training. However, maintaining a higher running speed may induce a greater musculoskeletal strain. Using a 45° change of direction may be an effective alternative to reducing acute neuromuscular load during repeated sprint training, with an even sharper change of direction being associated with a higher acute risk of both ankle and knee injuries. The high volume of decelerations has the potential to increase acute muscle fatigue.

In sprint interval training, longer rest durations show greater impairments in neuromuscular performance because they allow for max-effort bouts. Longer sprint intervals (up to 72 seconds) might have more neuromuscular demands than shorter intervals (15 seconds or 30 seconds)

Incorporating HIIT Training as a Non-Specific Conditioning Method Off-Season

After the in-season is over and before the official start of off-season training, most athletes transition to a period characterized by unstructured or partially structured training, reduced training load, and active rest strategies. During this period, the primary goal for athletes is to maintain fitness levels and technical skills while providing recovery and regeneration. It is important to note that if this period involves reduced training for too long (i.e., >2-4 weeks), the athlete will require a much longer preparation period to be ready for the subsequent competitive period.

My approach to metabolic conditioning during this period involves having athletes engage in a set amount of weekly extensive, sub-threshold aerobic activities that do not include sport-specific movements or decision-making while giving them autonomy regarding the training frequency.

Athletes get involved in HIIT training as soon as the off-season training officially begins. During the very early off-season, HIIT long involving generic run drills with no emphasis on decision-making is often utilized. As mentioned earlier in this article, this HIIT format involves a high contribution from both the aerobic and anaerobic systems. While it can be fatiguing for the neuromuscular system, the actual output is not high, which makes it an excellent choice for the earlier stages of training.

As the off-season progresses, HIIT short, combining generic running and sport-specific movements, begins replacing HIIT long. Decision-making, even if present, does not limit the achievement of the desired metabolic and neuromuscular targets. Late off-season involves both all-out effort and very high, but not all-out effort, repeated sprint intervals. These drills are mainly performed on the court and include sport-specific (competitive) formats, placing high demands on both the glycolytic and neuromuscular systems. The training considers the characteristics of playing positions, and decision-making demands are high. HIIT short intervals are occasionally programmed into the week to put an extra stress aerobic system.

It is worthwhile noting that incorporating non-specific metabolic conditioning into the off-season training program requires considering that athletes are still practicing and playing their sport. In the early stages of the off-season, when sport-related stress is minimal, there is a low possibility of interference.

However, as the off-season progresses and the volume and intensity of sports practices increase, it becomes crucial to make well-thought-out programming decisions. Too much allostatic load at the wrong time can harm performance and development. Therefore, it is essential to intelligently combine HIIT training with the sport’s stressors while adjusting its overall volume according to each athlete’s status.

In my system, additional non-specific conditioning always accompanies the nature of the stress related to the volume and intensity of sports practices and games. This approach ensures that physical preparation and sport-specific training work together, creating a balanced perception of stress and helping to prevent performance plateaus.

Generally, higher-intensity, lower-volume practices are usually paired with conditioning protocols that stress the neuromuscular and anaerobic systems while moderately stressing the aerobic system. This can include repeated sprint intervals or HIIT short with lower density but higher outputs. On the other hand, lower intensity, higher volume sports practices are often combined with tempo intervals or LISS training.

The most challenging practices of the week, which involve both high volume and high intensity, are commonly paired with HIIT short or, less often, HIIT long intervals, thereby stressing all systems. Occasionally, I might program very low-volume sprint interval training to challenge athletes mentally and physically.

An example of a late off-season training microcycle for team sport athletes.

Making Informed Programming Decisions with Firstbeat

Even if quantifying the exact physiological load of HIIT can be challenging, following the tips from the authors of “Science and Application of High-Intensity Interval Training ” makes achieving the desired results more manageable. However, prescribing HIIT based on predetermined metrics, such as the ASR or MAS, in team sports can be challenging due to various constraints. Firstbeat provides valuable insights into players’ external load parameters, including Movement Load and Intensity. It also measures internal load parameters such as TRIMP, TRIMP per minute, and Excess Post-Exercise Oxygen Consumption (EPOC).

This comprehensive data quantifies training volume and intensity while offering insights into how athletes respond to their training. In addition, Firstbeat evaluates parameters like aerobic and anaerobic training effects, providing real-time insights into each training session’s metabolic demands. Furthermore, it assesses an athlete’s preparedness status by comparing acute and chronic loads and measuring heart rate variability (HRV). With these insights, informed decisions about programming non-specific conditioning, including HIIT, can be made.

It is essential to recognize that while Firstbeat offers detailed insights into the neuromuscular demands of training by quantifying external load, it is also necessary to consider the specific movement patterns used during training. Understanding how these patterns relate to programming additional high-intensity interval training (HIIT) is crucial.

For example, when organizing a tactical session that involves a lot of high-speed running (HSR), it is advisable to avoid placing excessive strain on the hamstrings. However, if the goal is to specifically target those muscle groups such as in preparation for the high demands of a match then a HIIT sequence focused on high-speed running could be incorporated into the program.

One aspect often overlooked in high-intensity interval training (HIIT) is that its average movement intensity usually exceeds peak match demands. For instance, certain HIIT protocols can match the high-speed running distance of a 90-minute game in under 15 minutes. This applies to other metrics in different sports, like basketball accelerations and volleyball jumps.

Such overload may be unnecessary and could be avoided by breaking HIIT into smaller sequences with rest periods, helping to align average movement intensity closer to game demands. However, this might not be enough for optimal cardiorespiratory adaptations. Coaches must decide between longer HIIT sets for metabolic conditioning or shorter sets for match-specific intensity. In my practice, I mix various movement patterns within the same HIIT block alternating linear runs with multidirectional movements or jumps. This strategy helps reduce the average intensity of high-speed running, allowing players to train longer without risking a sudden workload increase.

Firstbeat Key Metrics

Conclusion

In an ideal scenario, all conditioning would be completed by playing and practicing the sport. While it can be challenging to replicate the physical and emotional stress generated during actual competition, there are instances when non-specific metabolic conditioning becomes necessary.

HIIT is a powerful and versatile option for off-season conditioning. By manipulating various HIIT variables, coaches can adjust the physiological demands placed on athletes. In my system, additional non-specific conditioning always accompanies the nature of the stress related to the volume and intensity of sports practices and games. Firstbeat provides valuable insights that help inform decisions regarding the programming of non-specific conditioning, including HIIT.

Download our Athlete Training Load Guide to learn more about the Firstbeat metrics and how they can help you optimize your team’s training, performance, and recovery.