Load management principles are used daily in high-end strength and conditioning/sports settings and are critically important in measuring relative injury risk and determining optimal load.
However, the concept of load management may not be limited to high-performance sports or training settings. There are principals of this concept that are applicable in non-sporting settings (eg. day to day activities, work, and leisure). Exploring the wider contexts to which load management principals can be used may assist in reducing overuse/chronic injury risk for the general population.
Let’s Talk Science
A concept developed based on the idea of an ideal training stimulus having the capability to maximise performance through the use of appropriate training loads while limiting negative training consequences (injury and fatigue). The ACWR describes two workload zones, the ‘sweet spot’ and the ‘danger zone’ which represent the likelihood of subsequent injury.
The ‘sweet spot’ is represented in the graph below as a ratio range between 0.8 and 1.3. The ‘danger zone’ is represented as a ratio greater than 1.5.
Calculating ACWR & Load: Acute vs Chronic
In a training setting, this is typically calculated over a 7-day block (average of daily acute workloads). Measures of the sessional rating of perceived exertion (sRPE) times by the duration of the training session would represent the acute load for a day. Example: If sRPE (perceived difficulty) of a 100-minute session is 5 this would equal 500 arbitrary units (AU) (5*100 = 500 AU).
The chronic load can be calculated as an average of the acute workloads.
Week 1: 500 AU
Week 2: 700 AU
Week 3: 600 AU
Week 4: 300 AU
Chronic Load: (500 + 700 + 600 + 300)/4) = 525 AU
ACWR: Acute Load (Week 5: 700AU)/Chronic Load – (700 / 525) = 1.3
To give some commentary to the above equation: If the acute workload for week 5 was to be 700 AU then the ACWR for that period would be 1.3. A value of 1.3 would represent the top end of the “sweet spot” bracket, meaning that the subsequent injury risk for that week is relatively low. If that acute load was to change to say 900 AU then the ratio would be 1.7 and the injury risk would be relatively greater.
Application to YOU
Both internal and external load is inevitable in the workplace, there is no hiding from the fact. The table above displays the application of the ACWR as a load management tool for individuals across a wide range of occupations. As you can see all scenarios have the capacity to create positive or negative outcomes. The outcome is primarily dependent on the preparedness of the individual to that specific task.
Looking specifically at the receptionist, the increase in acute load may come from working longer days during a busy period or working more days in the week to cover for a colleague who is sick for example. These factors can drive up the acute load, inherently increasing injury risk (eg. overuse injuries, such as a repetitive strain injury), leaving the individual unable to work.
However, this doesn’t only apply to occupational tasks…
Simple scenarios such as going for a 10km bike ride after just dusting your bike off from a 10-year absence of use or going on an overseas holiday where you may be walking over 10km per day while being lucky to clock up 2km at home during a normal day; both are examples of a spike in acute load far beyond that of the chronic load.
Take Home Points
- Ensure that you are prepared for any task you will be completing; whether it be walking, running, cycling, gardening, working, playing sport.
- Be mindful of what your body is used to and try to avoid the spikes in acute load for any given task; should you want to reduce the risk of developing any injuries.
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Strength and conditioning is a vital aspect for all young athletes performance and development.
There are often many questions asked when referring to a young athletes training regime, “when should they initiate a supervised strength and conditioning program?”, “Is it safe to do so?”, “Will their growth be affected?” These are all legitimate questions of concern to parents and caregivers.
The opportunity for children to participate in more competitive environments at earlier ages is a trend which has increased over the past years, driving the many questions around training, but more specifically, “when is too young to start an organised strength and conditioning program?”
The Australian Strength and Conditioning Association (ASCA), hold the position that if a child is ready to participate in organised structured sport that are generally ready to participate in a supervised resistance training program. It is of the opinion that the earliest a child should begin a structured strength program is 6 years old, this starting age is fluid and very much dependent on the ability of the child to follow clear instructions. Training intensity and loading protocols vary depending on age and development. A rough guideline for athletic development can be seen below.
6-9 years of age: modification of body weight exercises and light resistance
9-12 years of age: 10-15 RM; (maximal loading approximately 60% maximum)
12-15 years of age: 8-15 RM; (maximal loading approximately 70% maximum)
15-18 years of age: 6-15 RM; (maximal loading approximately 80% maximum)
The concept of this outline doesn’t differ much from the mindset and approach we would take with an adult, regardless of their training experience. We would still check to make sure the technique is sound, that everything is moving well and functioning as it should before adding any load. Yes, someone with more training experience will likely move through this stage faster but the concept remains, the only difference being recommended age brackets in regards to progressions when dealing with youth.
Injury Risk, Growth and Height
Touching back on the question of safety, the effect on growth and eventual height. Evidence suggests that the key growth and development phase in childhood and early adolescence may be the most beneficial time to implement weight-bearing activities. Such as during a time while the body is continually developing bone mineral density, mass, and structure. In regards to growth and height, there are no studies to indicated that resistance training will effect eventual height or cause injury to growth plates.
Youth typically have lower levels of joint and muscle sprains when compared with adults. Injury risk for youth in strength programs generally arise from unsupervised accidents either with equipment or from inappropriate training loads. This is where a qualified supervisor/coach becomes critical to the safety and effectiveness of a strength and conditioning program.
Let’s get onto the good stuff, the benefits!
A dynamic, multi-faceted approach to training has widely been shown to reduce injury risk amongst young athletes, very much similar to the effect it has on adults. It is vital to initially develop fundamental motor patterns in youth athletes that can then be transitioned over to competition or into the gym. Generally, athletes that regularly participate in a well-structured training program will often suffer fewer injuries and be able to recover faster from any injury sustained.
Benefits of resistance training in youth:
- Improvements in muscular strength
- Power production
- Running velocity
- Change-of-direction speed
- General motor performance
Integrative neuromuscular training (INT) is a conceptual training model that describes a training program that incorporates a range of general and specific strength and conditioning activities specifically designed to enhance health and skill-related components of physical fitness. Health-related components including flexibility, muscular strength, muscular endurance, body composition, and cardiovascular health. Skill-related components including coordination, speed, power, balance and agility.
By taking a multi-faceted approach for the athlete we are ensuring that they are physically prepared for all requirements of their chosen sport or activity.
The below graph represents the difference between the initiation of these integrative training techniques during pre-adolescence and adolescence compared to sport only and no sport.
The graph displays a clear benefit of initiating neuromuscular training during both pre-adolescence and adolescence stages of development. Neuromuscular training initiated earlier in the developmental stage likely leads to greater neuromuscular performance and greater capacity above mature performance potential.
Take home points
- If a child is ready to participate in organised structured sport, they are generally ready to participate in a supervised resistance training program.
- Resistance training initiated at an early age is beneficial to physical growth and development, while not being associated with growth abnormalities and increased injury risk.
- A multi-faceted approach to strength and conditioning (such as the integrative neuromuscular training model) is beneficial for injury prevention, performance enhancement, and motor development + capacity.
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The holiday season is fast approaching, organized sports are coming to a halt, work is winding up and many of us are embarking upon holidays. The Christmas break is a time where we are often given the opportunity to reconnect with friends and family while having a break from a regular schedule. While this opportunity to recharge may be necessary, it can also be to the detriment of any fitness progress and goals you have achieved throughout the passing year. Fitness loss is commonplace, not only during the Christmas holidays but during any extended period of reduced physical activity and we often refer to this effect as detraining.
Detraining and the Residual Training Effect:
Lets talk about detraining, you may have heard about it somewhere along the grapevine or maybe you have had first-hand experience with it, most likely the latter. The relationship between detraining and the residual training effect revolves around the idea that after cessation of training or an acute reduction in volume the body begins physiological processes which slowly untie any positive adaptations to training we may have made (detraining/deconditioning). It is these physiological characteristics that when grouped together make up what we call fitness components. These components include speed, maximal strength, aerobic endurance, strength endurance and anaerobic endurance. Now, while these may not all relate to you, there are most likely one or two which are inclusive in your fitness goals (no matter how basic or specific they are).
However, it may not be all doom and gloom. It is important to know that not all of these characteristics deteriorate at the same rate, some are much more resilient to detraining than others.
The table below gives an outline of how long the physiological adaptations are maintained during a period of detraining.
The Residual Training Effect
What effects the residual training effect?
- Duration of training before reduction or cessation
- Training age and physical experience
- Intensity used during the detraining period (moderate to high-intensity exercise reduces rate)
You may be asking “how does this relate to me?”
As shown in the table above we can see that speed is the most susceptible to change (2-8 days), whereas maximal strength and aerobic endurance are the most resilient (25-35 days). If your goals are to maintain speed and strength endurance it would be counterproductive to completely stop training, these components would best be maintained with a few short sprint and full body hypertrophy sessions during the break. Whereas if your goals are to maintain maximum strength and aerobic endurance; While it would not be ideal to completely stop training, the reduction in training volume would not have such a detrimental effect as the components mentioned previously.
So what should you take out of this?
- Try to integrate some moderate to high-intensity training into your break to slow down these detraining effects.
- Short sessions with a focus on the components that are most susceptible to change or relate closest to goals are recommended.
- Sports where repeated sprint ability (RSA) is critical to performance (AFL, Soccer, Basketball), should focus training on sport-specific needs for the athlete and include short sprint sessions. There is not a great need to prescribe or complete long aerobic/anaerobic endurance sessions during the break where time is often scarce.
- Reflect on your current and previous goals and how this concept relates to you if you are planning on taking a break.
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