Physical training foundations
Introduction
Exercises are tools to differentially stimulate physiological systems, with an end-goal of inducing beneficial adaptations in those systems.
| Analogy | Physiological component/system examples |
|---|---|
| hardware | muscle fibers, connective tissue, bone |
| software | nervous system control |
| local fuel storage | intra-cellular fat and glycogen stores |
| global fuel storage | adipose tissue, liver |
| pumps / pipelines | cardio-vascular system, lymphatic system |
On the other hand, this cool talk by Philip Ball points out limitations of machine metaphors in describing biological systems.
My motivation is general health. When I started thinking about this a couple of years ago, I was already willing to put in time and energy towards improving my physical health. Yet, I was unclear about which exercises to adopt, how often to do them, how to calibrate effort etc. This is a common problem that many in a similar situation face.
To understand these topics a bit better I worked my way through a standard reference manual for strength and conditioning coaches (Haff and Triplett 2015) and a handful of relevant review papers. I continue to calibrate the utility of concepts I picked up this way by incorporating them into my own practice. Below is a version of key concepts and crude-but-useful ways to reason with them towards building a rounded physical training program for yourself.
This article is organized around the main components of conventional strength and conditioning programs: cardiovascular-, resistance-, and plyometric training.
General notes
- Training variables are measurables or choices that can be manipulated to induce different training stimuli. Intensity, duration, rest intervals, frequency etc. are all examples of training variables.
- Within a session, choose a stimulus that preferentially and adequately challenges the target physiological systems.
- Vary training variables across sessions so that relevant physiological systems can
- accommodate the imposed demand.
- adapt in a desirable way to the stimulus.
- avoid an overtraining-related breakdown.
- Periodization is the strategic manipulation of training variables in cyclic patterns over different time-scales (weeks, months, even years) aimed at accumulating adaptations.
1 Cardio-vascular training (CVT)
Walking, running, cycling, swimming, stair-climbing, and cross-country skiing, ski-ergs, rowing etc. are all activities that can be used for cardiovascular training (CVT). Intensity and duration of activities are key training variables. In my opinion, the qualitative way of specifying these in Table 2 is a reasonable level of detail in the context of CVT for those starting out. Quantitative measurements (e.g. with heart rate monitors, blood lactate measurements, VO2max tests etc.) have their place, but are not a pre-requisite for an effective plan.
| Session | Intensity | Duration |
|---|---|---|
| A | High | Short |
| B | Medium | Medium |
| C | Low | Long |
High intensity and short duration sessions
- These tend to be relatively more taxing (compared to a low intensity session with the same activity) on connective tissue (i.e. bones, joints, cartilage).
- The main goal for such sessions is to stimulate adaptations for maximal power output, and faster recovery after bouts of maximal effort.
- The duration and intensity of effort within a session can be selected to focus on different energy systems.
- The anaerobic system is the primary responder for bouts of maximal effort that last up to 30 seconds.
- The aerobic system is the primary responder for bouts of effort sustained for > 1:00 minute.
- Such sessions are aligned with the idea of interval training, e.g. HIIT, Fartleks.
Medium intensity and medium duration sessions
- The idea is to exercise at as high an intensity that can be sustained for the entire workout duration.
- The main goal for such sessions is to stimulate adaptations for sustained power output.
- The level of lactate buildup (a byproduct of anaerobic breakdown of glucose within muscles) in the blood is a key indicator of such intensity.
- Such sessions are commonly known as anaerobic threshold-, lactate threshold-, or tempo- workouts.
I’ll highlight some terms that have specific definitions in research settings, but the distinctions are not of practical importance for effective training for the general population.
- Aerobic threshold (AeT), ventilatory threshold I (VTI), FATmax, upper ends of zone 1 (3 zone model) or zone 2 (5 zone model) correspond to a similar training intensity. Subjectively, this is a steady effort at the upper end of what feels easy to sustain for > 30 minutes.
- Analogously, anaerobic threshold, ventilatory threshold II (VTII), and lactate threshold (LT) also correspond to a similar training intensity. Subjectively, this is a hard effort that can just about be sustained for 30 minutes. ****
Low intensity and long duration sessions
- These are easier (relative to the fast and short sessions) on connective tissue.
- The main goal for such sessions is to stimulate adaptations for efficiency and endurance of related systems.
- A key adaptation we seek through such sessions is increased utilization of fat as the energy substrate.
- These sessions correspond to working out at or below aerobic threshold.
Exercise selection & frequency
- Modify any activity e.g. using a treadmill, stationary bike, rower, ski-erg, or being active outdoors to fit the intensity and duration pattern for CVT session A, B, or C. One can mix activities to manage fatigue in a particular system (e.g. swimming for CVT session C would help manage fatigue in muscles and joints involved in running in CVT session A).
- Cycling through sessions A, B, C over a span of 7-10 days at a time would be a good starting point. If this ends up inducing too much fatigue, reduce the effort level within sessions instead of cutting down on sessions, Figure 1.
- I recommend choosing a conservative starting point (let’s say 20% below current ability) and progressing over a few weeks to get close to actual ability.
- As a rule of thumb, change just one of the training variables in a direction that increases challenge by a small amount (let’s say 5% per week - and even less if changing multiple variables simultaneously).
- Repeating the same activities for a month or more would make it easier to track progress, and fine-tune your subjective feeling of effort.
- I’d like to reiterate that these are not strict prescriptions, but serve as starting point to fine-tune as you spend time and gain experience.
📊 My recommendations here fall somewhere between the pyramidal and threshold models. (Casado et al. 2022) review common ways of distributing training volume and intensity for CVT (pyramidal, threshold, polarized models) in runners, but the conceptual basis remains the same for any CVT-related activity.
2 Resistance training (RT)
Exercises using dumbells, kettlebells, barbells, specialized machines, and bodyweight can all count towards resistance training (RT). Training variables commonly manipulated in resistance training include load, repetitions, sets, tempo, and rest intervals. Such variables can be adjusted to focus more on adaptations for hypertrophy, endurance, power, and strength. These are not entirely independent attributes. The different kinds of training stimuli lead to preferential but not exclusive development of these attributes.
Path to learning exercises
- Learning any exercise involves acquisition, refinement or consolidation of motor skills (i.e. motor learning).
- This requires concentration and repetition (much like learning to play music on an instrument or a dance sequence).
- If access to certain positions demanded by the exercise is not currently possible (i.e. tightness, joint restrictions etc.), choose an exercise regression that you can load without discomfort.
- Aim to learn a motor pattern that uses the intended muscle groups effectively and consolidate it within available ranges of movement.
- Keep working on end ranges with lower load till you can do progressed versions for that exercise.
- Investing time to study anatomy and biomechanics underlying the movement patterns will help to adjust form and effectively stimulate the intended muscles.
Exercise selection and order
A reasonable starting point is to pick one or two exercises for each of the following:
- Squat pattern
- Hinge pattern
- Vertical pull
- Vertical push
- Horizontal pull
- Horizontal push
Rough reasoning:
- These movement patterns cover a broad range of muscle groups.
- Prime mover (also known as agonist) muscle groups across these movements are largely non-overlapping.
- So muscle fatigue from one exercise is less likely to interfere with another exercise that preferentially stimulates a different muscle group.
- The ordering of exercise within a session is not too critical for a basic training plan; I personally prefer to do lower body exercises first (squats and hinge patterns here) to prioritise stimulating the bigger muscle groups while my nervous system feels more fresh.
Sets & Repetitions
Work sets (i.e. excluding any warmup sets) of any exercise within a given session follow one of the following patterns:
- (~3) sets with medium load and high (~10) repetition
- (~3) sets with high load and low (~5) repetitions
This holds for each exercise (and therefore for muscle groups used in that exercise). What qualifies as medium or high load depends on subjective ratings of effort (RPE, discussed below and Table 3).
Rough reasoning:
- Medium-load, high-repetition sessions tend to induce more fatigue, but are easier on the joints.
- Such sessions are thought to bias training towards stimulating hypertrophy.
- High-load, low-repetition sessions are harder on the joints.
- Such sessions are thought to bias training towards strength adaptations.
Tempo
- Slowing the eccentric phase of the exercise in particular is thought to promote adaptations in related connective tissue (i.e. tendons, ligaments, and cartilage).
- Tempo is commonly indicated as time (in seconds) spent in the
eccentric / pause / concentric / pausephases of the movement (e.g.3/0/2/0). - Training with a focus on tempo, also commonly known as tempo training.
Load & Effort
- An appropriate selection of load depends on the sets and repetitions scheme, the tempo at which the exercise is performed.
- Tracking rated perceived exertion (RPE) and repetitions in reserve (RIR) can be used to select an appropriate initial load, see Table 3.
- Hovering between 7-9 RPE or 2-5 RIR are typical guidelines (RIR may be easier to judge accurately for less experienced individuals).
- Background stress / sleep / nutrition will also influence what loads correspond to a given RPE and RIR.
- Logging load on each exercise, and adjusting so that it trends upwards on a time scale of weeks is a common way (but clearly not the only way) to judge progress.
| Description | RPE | RIR |
|---|---|---|
| Little to no effort | 1-2 | - |
| Light effort | 3-4 | - |
| Moderate | 5-6 | 4-6 |
| High, vigorous | 6-7 | 2-4 |
| Very hard | 8-9 | 1 |
| Max. effort, nothing more left | 10 | 0 |
Rest between sets
- The goal of rest in between sets in RT is to allow adequate time for anaerobic systems to recover.
- Too much rest makes sessions unnecessarily long, too little rest prevents muscle fibers from operating at capacity across sets.
- 2-5 minutes of rest between sets is a rough guideline for resistance training Freitas de Salles et al. (2009).
- Note that this is a recommendation for muscles used in a given exercise.
- So to make workouts more efficient, one strategy is to alternate between exercises that don’t require the same muscle groups i.e. supersets. Push and pull variations can generally be alternated this way.
- Supersetting becomes easier once the motor patterns are well-established for the exercises (i.e. it does not interfere with technique).
3 Plyometric training (PT)
- Plyometric exercises are aimed at improvements in the re-use of elastic energy and the stretch reflex for movements that involve a stretch shortening cycle.
- A key feature of movements considered in plyometric training is that they are generally executed at fast time scales (e.g. ~200 ms or less).
- If the same movement is performed slower, the passive elastic energy dissipates (e.g. as heat), and the stretch reflex is not coordinated with the voluntary contraction for the desired movement.
- Lower body movements: hopping, jumping, bounding, etc. and upper body movements: throwing, catching etc. are examples of plyometric exercises.
- Peak force, rate of force development, tolerance to impact etc. are key attributes we seek to improve through plyometric training.
- Such exercises can be used to introduce graded and controlled exposure to impact (short duration, high force).
- They can also be used to improve sport-specific athletic skills.
- High impact stimuli is thought to contribute to improvement/ maintenance of bone health.
- It also is a way to recruit and maintain motor units that otherwise are only stimulated with heavy loads in RT.
The prescriptions for plyometric training are not as well-studied as for CVT and RT, (Davies, Riemann, and Manske 2015). However, the core principles of identifying training variables and systematically varying them to induce adaptations while avoiding overtraining remain the same.
Exercise selection
It is reasonable to include some version of hopping, bounding, throwing, and catching exercises at intensities that
- can be tolerated (alongside RT and CVT sessions).
- are within available range of motion.
- cover a broad range of stimuli.
A broad classification of exercises is helpful in this regard, and I personally like the one presented by (McInnes Watson 2024) (adapated here in Figure 2).
Frequency, intensity
- Less intense versions of plyometric exercises (e.g. two-leg pogo hops) can be performed in every RT or CVT session.
- More intense versions can be performed once (per category, e.g. trunk, lower body, upper body) every week.
- A rough starting point is 2-3 sets each with 20-40 rhythmic repetitions for low intensity exercises, and 2-3 sets of 5-10 repetitions for high intensity exercises.
- Do these at the beginning of workouts, when feeling fresh.
- Do these with intention and rhythm.
- Do not perform to failure / fatigue.
Parting thoughts
- Find exercise regressions that feel like a comfortable entry point, and then use it as a base to progress on by adding challenge through training variables (load, range of motion, tempo etc.).
- Progressing on the same exercise for a chunk of time (e.g. 2-3 months) is helpful to both, consolidate the movement pattern, and deliver an effective stimulus for physiological systems to adapt to.
- Learning and fine-tuning movement can take time. Moreover, good technique may not feel natural right away. Film yourself, share it with a qualified / trusted coach for feedback and recommendations to adjust movement patterns.
- Keep trying related variations (e.g. different exercises, movement ranges, equipment etc.) separate from training, with no or low load. The goal of such exploration is to get a better feel for how movement combinations fit together.
- Performance and fatigue accumulated within any given session depends on background stress / sleep / nutrition etc., so be kind to yourself and focus on consistency in practice over timescales of months and years.
Building an understanding of these physiological systems and their inter-dependence is helpful to gain a more intuitive feel for physiological bottlenecks, desired adaptations, and their relationship to training variables. Video lectures on this playlist by Jacob Goodin can be a good starting point to learn about these topics in the context of strength and conditioning.
Acknowledgements
Polina Kosillo and Mayank Sanganeria for discussions.