Getting Started With (II) – Kettlebells

The GSW series presents focused applications of Analytic Fitness™ with a 2.500-word cap (excluding theory and analysis, kept in asides and footnotes, with no set limit) for an estimated reading time under 15 minutes.

Getting Started with Kettlebells

Kettlebells can satisfy everyone’s fitness needs, from couch potatoes to seasoned athletes, and anyone in between.

In fact, I’m about to go out on a limb and propose that if you find yourself at either extreme of that spectrum, the best approach to getting started with kettlebells is actually the same. But that’s some mildly-crazy stuff and as such, I’ll build up to it and save it for last. As is per the purpose of this series there isn’t really anything analytically new but there’s a boatload of asides with geeky stuff. Now for the plan:

  • Step 0: Pick the right bells. The pros and cons of competition kettlebells.
  • Step 1: Everybody needs stability. A minimal kettlebell-based stability routine that doubles as a mobility drill.
  • Step 2: Everybody needs more stability. A plea to people who sit too much for learning the Turkish Get Up.
  • Wrapping up: Get stable, dammit! Why stability training is probably for you.

Finally, given the importance of mechanical stability in this post, I’ve appended below a reasonably self-contained Crash Course on Mechanical Stability to help new readers navigate Analytic Fitness™ intricacies or refresh the memory of seasoned readers. Speaking of which…

Special thanks

A distinctly loud shoutout to Avocado Gourmet @daHuaba12 whose visible contribution to this post (Fig. 1 & 2) was outweighed by far by his invisible contribution. Subsequently, @daHuaba12 was awarded the first-ever Analytic Fitness™ Level II certification.


From Anders Bergmark (1989) Stability of the lumbar spine
Acta Orthopaedica Scandinavica, 60: sup. 230, p. 27.

A Crash Course on Mechanical Stability. Let’s begin with a reminder about Anders Bergmark’s biomechanical model of joint stability. On the left-hand side of Fig 6.5 from (Bergmark, 1989:27) the joint is maintained in proper alignment when subjected to torque (moment, moment of force) M. The force F from the muscle is sufficient to maintain this alignment. The system is mechanically stable iff, for some small additional torque ΔM adding up to M, the muscle could maintain the joint in proper alignment, that is, pull it back to alignment without voluntary contraction (as with moment M). Bergmark’s main hypothesis is that muscles have their own mechanical stiffness similar to the stiffness of springs, that serves as a simplified mechanical model for muscles (see TFS (IV): Stability (2), A Thought Experiment for details).

Bergmark does not specify the physiological correlate of mechanical stiffness but assumes explicitly that it is not under the direct control of the CNS (the CNS corresponds to the adjustment screw of a spring). For all purpose and intent, we can equate stiffness with muscle tone, that is, the residual contraction of muscles at rest (when no voluntary contraction occurs and absent spasms, etc.). An important assumption of Bergmark’s model is that our joints are not in stable equilibrium even absent pathologies that may affect joint alignment (such as muscle imbalances caused by too much sitting, see Move Your Sleepy Ass Inhibited Gluteal And Abdominal Wall Complex,A Theory of Sleepy Asses“). Unstable equilibrium lowers metabolic maintenance costs (muscle contraction costs energy) and is relatively safe as long as the CNS can increase muscle tension reactively when needed.

CNS reaction times are not always sufficient to protect joints against destabilizing events. Accordingly, the CNS may increase mechanical stiffness preventively (under the spring nalogy, tighten the screw) when some possibly destabilizing events are anticipated. This phenomenon can be harnessed for training purposes, for instance with exercises variations that introduce unpredictable micro-movements, like bench-pressing with a bamboo bar or juggling water jugs (cf. Trick Train Your CNS, Get Stronger) and using kettlebells with a bottom-up grip (cf. AFD: Loaded Carries).


Step 0: Pick the Right Bells

Unlike ‘fitness’ kettlebells that come in all shapes and form, competition kettlebells have the same shape irrespective of their weight.

With competition kettlebells, ‘sizing up’ is a no-brainer:once you have mastered a technique with one size, you just need to become stronger and won’t have to re-adapt to a new shape. With ‘fitness’ kettlebells, that’s never guaranteed (and let’s not dwell for too long on what ‘fitness’ means here: it’s just working fine to exclude competition kettlebells from search results). By the way, I write ‘size’, I mean ‘weight’, and when I write ‘bell’ I mean ‘kettlebell’. Also, there are different qualities of competition kettlebells but that’s a side-show (Kettlebell casting).

The large jumps between kettlebell weights seem to be a liability but it’s really an asset.

Pavel Tsatsouline

Competition bells sizes range from 8kg to 48kg, with a universal color code for each 4kg increment between 8kg and 32kg. There are intermediate sizes, which may seem a good idea but really isn’t. The best argument for ‘big’ jumps is that they force to “put the volume in” (and thus get enough quality practice) in order to get stronger. Pavel Tsatsouline gives a lively presentation of this argument in this video [1:02-1.47]. [1] There are some deliciously geeky details about the size progression, too (Kettlebell Math). With this in mind, 2 competition bells 4kg apart make the best starter kit: either 1*8kg+1*12kg (absolute beginner, weak, or cautious) or 1*12kg+1*16kg (anyone else). And in case you wonder why I’m not recommending dumbbells, there’s an aside for that (Dumbbells are dumb, Kettlebells are smart).


Kettlebell Casting. There are essentially two types of competition kettlebells: single-cast kettlebells and welded kettlebells. Single-cast kettlebells are cast in a single mold (duh) with a more or less hollow body (depending on size) and center of mass of the bell kept close to the handle. Welded bells are made with separate molds for the body (an empty shell) and the handle, which is welded to the body. Filler is added in the body according to size. Welded kettlebells are overall of inferior quality and all have the same disadvantages (handles may break if you drop the bell, and filler gets loose and may offsets the balance of the bell). Overall, for welded kettlebells, the cheaper the better. Single-cast kettlebells ar worth the investment if you’re serious with your practice, even more so if you intend to try out 2-hand lifts. If you live in the US or Canada and can afford Kettlebell Kings “competition” or “adjustable competition” models (for the latter, the shell and handle are single cast), go for it. If you live in Europe in a country where Wolverson ships their GS competition kettlebells and can afford them, go for them instead (but stay away from their “Russian” model, which is not Russian at all: its handle is too far from the body, which offsets the center of mass and makes them less comfortable to use). If you need more specific advice, leave a comment or send me a message on The Older Avocado’s Facebook page and I’ll help you find the best shop nearest to you.

Kettlebell Math. Considering the ‘official’ competition sizes (8kg, 12kg, 16kg, 20kg, 24kg, 28kg and 32kg) and setting n0 = 8kg (and ni>1 = nn-1+4kg) the progression obeys the following function:

ni>0 = ni-1+[ni-1*1/(2+(i-1))]

In semi-vernacular English, the marginal weight increase for a term of an element of the sequence n1, n2, …, relative to its predecessor is a decreasing function of the absolute weight of the predecessor.

In full vernacular: assuming that you “put the volume in”, moving up one bell size becomes easier as the absolute weights gets heavier. A protocol for “putting the volume in” based on manipulations of total load (reps*weight) and intensity (load/reps) and takes advantage of “big” jumps is presented in the next section. The nifty diagram of Fig. 1 below represents the absolute weight, the absolute weight increments (step) and the relative weight increase in %-age of the predecessor (on the same scale as weight, beginning with 12kg being 8kg + (8kg*0.5)). The absolute weights are color-coded with the international code for competition bells sizes.

Fig. 1. Kb weight increase with a starting weight of n0 = 8kg
(by Avocado Gourmet daHuaba, AF™ lv. 2)
[Right-click and open in a new tab to enlarge.]

Dumbbells are dumb, Kettlebells are smart. Kettlebells are portable, but so are dumbbells, and adjustable dumbbells are cheaper than a kettlebell starter set, let alone quality adjustable kettlebells. So why buy a piece of equipment with a fixed weight that you’re going to out-strength eventually? There are tons of reasons, but they boil down to two:

  • Kettlebells, however light, can challenge stabilityi (i ∈{1,2}) in ways dumbbells can’t. Switching from regular to open palm to ‘waiter’ style to bottom-up while playing with your base of support challenges balance (stability1) and mechanical stability (stabilit2). You can’t bottom-up a dumbbell.
  • Kettlebells, however heavy, let you relax your grip. Some kettlebell exercises have built-in ‘rest’ positions where you can relax your grip and let your bone structure bear the weight. You can’t relax your grip with a dumbbell without dropping it.

Stabilityi (i ∈{1,2}) is a recurring theme in this post but nothing illustrates better grip variety than the YouTube video below where Steve Cotter demonstrates over a dozen press variations of presses (and suggests even more through grip variations) and overall shows how to use kettlebells creatively to apply the principle of overload even without increasing bell size.


Step 1: Everybody needs stability2

Mechanical stability (stability2) is a physical quality both misunderstood and underrated.

Mechanical stability is often confused with balance even by professionals such as clinicians, physiotherapists, and coaches who should know better (see TFS (IV): Stability (2), “A Scientific Revolution (?)“). That’s an issue but there is worse: how the central nervous system (CNS) maintains joint stability has consequences that are by-and-large ignored by coaches and physiotherapists.

One of these consequences is that in most cases, end-range of motion (E-ROM) is not accessed without sufficient loading, and the weight of one’s own body does not typically qualify as “sufficient” (for the geeky details, see E-ROM and the Load-Injury Curve). Fortunately, a light external load suffices to safely access E-ROM. Below is an example of stability2 routine, followed by a few comments about each of the exercises and which E-ROM (if any) are accessed.

  1. Hip Hinge. Mobilizes the hip joints (dynamic) and the spinal joints (static). Expect no training effects, but even a light bell can help ‘feel’ the co-contraction that maintain spinal stability.
  2. Bottom-up Goblet Squat. The bell loads the hip, knee, and ankle joints (dynamic, with E-ROM and near-E-ROM for the last two), as well as the spinal and shoulder joints (static, both maintaining posture); the bottom-up grip makes a light load challenging.
  3. Bottom-up Halo. Mobilizes the shoulder and thoracic spinal joints (dynamic, Extension E-ROM for the latter if done correctly, “flattening” the natural kyphosis) and the lumbar spinal joints (static) with a co-contraction of the abdominal wall to keep the ribcage down; again, the bottom-up grip (behind the head) makes a light load challenging
  4. Overhead Triceps Extension. Mobilizes the shoulder, elbow, thoracic spinal, and wrists joints (dynamic, to elbow E-ROM in both flexion and extension, and to thoracic spinal E-ROM in extension only)
    and the lumbar spinal joints (static) with a co-contraction of the abdominal wall to keep the ribcage down.

The routine is best performed as a reverse pyramid (RP) circuit: n reps of each of the 4 exercises in sequence, followed by n’ reps of each exercise in sequence, and then n” reps, with n>n’>n”. A good starting point is n=3, n’=2, n”=1, and a good end-point is n=5, n’=3, n”=2 (shown on video). In my experience, this pyramid progression suffices to transition to a heavier bell size when n=5, n’=3, n”=2 is reached with the current size (re-setting n=3, n’=2, n”=1 with the heavier bell). This experience can be supported analytically with some geeky math (Kettlebell Math, cont’d).


E-ROM and the Load-Injury Curve. The Load-Injury curve is a hypothesis proposed by Cholewicki and McGill in 1996 in their application of Bergmark’s theoretical model to the in vivo spine. Although Cholewicki and McGill specify this hypothesis for spinal joints only (see the caption of the curve below), Bergmark’s model extends to other joints, and since the curve is a consequence of Bergmark’s model, so would be its generalization to other joints.

Fig 9 (p.9) from Cholewicki, J., & McGill, S. M. (1996). Mechanical stability of the in vivo lumbar spine: implications for injury and chronic low back pain. Clinical Biomechanics, 11(1), 1-15.

E-ROM is often where instability is the highest (in particular due when it involves longer moment arms) and thus where the risk of joint failure is at its highest. Therefore, getting closer to E-ROM increases the risk of injury through joint failure. Cholewicki and McGill give the example of how flexing lumbar spine to picking a pencil cause enough instability for the spine to buckle (Cholewicki & McGill 1996:9). Similarly, reaching out to the back seat of the car can cause enough instability in the gleno-humeral joint to cause a shoulder injury. Ironically, a shoulder mobility drill with a broomstick is less likely to have similar consequences if one has ‘tight’ shoulders, since the compressive forces that result from co-contraction of the muscles surrounding a joint are protective for that joint (see AFD: Loaded Carries, Study I: Strongman Carries). Hence, it seems wise to apply some load in addition to the load of the body itself when accessing E-ROM in cases that may cause instability. This vindicates yoga asanas that manipulate gravity or isometric tension to increase the load on joints, which are better than passive stretching, or active stretching such as contract-relax (since the E-ROM is access after during the relaxation phase, where co-contraction is inhibited). The video below gives an example of how loading can be applied to shoulder mobility drills in order to protect the gleno-humeral joint through co-contraction of the surrounding muscles.

Kettlebell Math (cont’d) The RP progression from the main text is a variation on McGill’s (2016, p. 237-238) who recommends it for progressive training of strength (see next section, Post-Rehabilitation Training and Chronic Sitting). McGill scheme is 5/4/3 for a single unilateral exercise, which is equivalent to a 1-exercise circuit. Assuming a 3/2/1 to 5/3/2 progression beginning with an 8kg kettlebell, Fig. 2 illustrates how the total load waves: as the absolute weight of the bell increases, the difference between the 5/3/2-workload with ni and the 3/2/1-workload with ni+1 increases. As a result, sizing up amounts to de-loading, even though the intensity, expressed in total workload/reps, increases. The increase in intensity so defined is expressed by the sequence 8, 12, 16, 20, 24, 28, 32 (verification left to the reader) so that the relative increase in intensity is rexpressed by the same curve as the relative increase in kettlebell weight from Fig. 1.

Fig. 2. Waving total workloads for RP progression
(by Avocado Gourmet daHuaba, AF™ lv. 2)
[Right-click and open in a new tab to enlarge.]

Step 2: Everybody needs more stability2

Mechanical stability (stability2) is a physical quality both misunderstood and underrated.

Mechanical stability is often confused with balance even by professionals… “Wait,” I can hear you say, “haven’t we gone through that already?” Well, we have, but for one thing bis repetita placent, and for another, there’s yet another a point to be made about mechanical stability: we sit a lot, and this ruins that. I’ve already covered the topic in Move Your Sleepy Ass Inhibited Gluteal And Abdominal Wall Complex,A Theory of Sleepy Asses” and I’m not going through it all over again, but here’s a summary of the main points:

  • sitting inhibits some muscles while over-activating others (independent of CNS control); therefore:
  • sitting raises risks of joints injury both: (1) at low loads, where
    muscle imbalances further compromise joints that are not in stable equilibrium, to begin with (cf. A Crash Course on Mechanical Stability); and: (2) at high loads, where muscle imbalances can affect movement mechanics and increase the risk of tissue failure.

The good news is that stability training based on textbook biomechanics is a no-brainer: given a task t performed at a given load, one first progresses to a task t’ that transfers to t, but such that t’ has an increased mechanical stability demand. An example would be progressing from a kettlebell rack carry to a kettlebell bottom-up carry. Task t’ promotes the co-contraction of muscles surrounding the joints involved in the task through increased CNS control. Improved CNS control then allows to safely increase the load in task t with a subsequent decreased risk of injury.

This strategy assumes however correct movement mechanics in the execution of task t. And that’s were sitting comes into play: excessive sitting causes pathological movements and motor patterns that need to be addressed (re-patterned) in order to prevent risks of injury and that’s where the Turkish Get-Up (TGU) comes into play. First, let’s have a look at the exercise (or more accurately, to its reverse form) performed by yours truly.

[T]he 14 stages in the TGU can be viewed as a continuously varying set of functional movement “problems” that must be “solved” by the neuromuscular control system.

St-Onge et al. (2019:24)

Now for some details. Rather than making up shit on my own, I’ll borrow to St-Onge, Robb, Beach Howarth (2019), A descriptive analysis of shoulder muscle activities during individual stages of the Turkish Get-Up exercise, Journal of Bodywork and Movement Therapies, 23 (1):23-31. In this study, the authors distinguish 7 states in each of the “Up” and “Down” phases of the TGU, for a total of 14 (see below Fig. 3). Based on the complexity of this sequence of motor tasks, St-Onge et al. propose that the TGU is the motor-learning equivalent to a problem-solving task (or more accurately, a sequence of problem-solving tasks). Although the approach is descriptive and limited (by the authors’ own admission) by the absence of a biomechanical model of the shoulder, the TGU-as-problem-solving dovetails Bergmark’s biomechanical model of joint stability, in particular, relative to how CNS control of muscle stiffness would increase in anticipation on a possible instability during the transitions between TGU stages.

Fig. 3 The 7 stages of a TGU according to St-Onge et al (2019)

Interestingly, solving the “TGU problem” requires the correction of the main pathological consequence of sitting, namely: (1) a sleepy ass an inhibited gluteal and abdominal wall complex; and: (2) an excessive kyphosis. Correcting (2) goes a long way to relieve stress on the lower back, which makes the TGU a great lower-back pre-habilitation drill on top of everything else. I’ll leave the details for an aside (Post-Rehabilitation Training, Chronic Sitting, and the TGU), but I can propose a practical example of strategy to solve the TGU-problem and get rid of (1) and (2) that I’ve used to teach the TGU to the personnel of the Philosophy Department at Lund University in 2017-2018.

There is some shameless promotion for the ebook at the end of this post, but all the proceeds go to “Iron vs. Leukemia (and Other Cancers)” so I have no problem advertising.


Post-Rehabilitation Training, Chronic Sitting, and the TGU. Rehabilitation is a form of training with limited goals (guaranteeing blood flow and proprioception while letting the injured part heal). When the erstwhile injured limb can move again, pathological motions and motor patterns caused by “moving around” or “training around” the trauma need be addressed. Motions and motor patterns, pathological or not, are often called “engrams”, a term of art denoting the patterns of co-activation of motor neurons in a muscle or muscle group resulting from repeated movements. For all purpose and intent, motor engrams can be taken to interpret the notion of “muscle memory”. So understood, post-rehabilitation training aims at overwriting pathological muscle memory (aka creating new engrams/muscle memory).

Fig. 4. McGill’s Post-Rehabilitation Training Protocol

In Low Back Disorders: Evidence-based Prevention & Rehabilitation (3rd ed), Dr. Stuart McGill proposes that post-rehabilitation training should proceed along 5 stages illustrated in Fig. 4 (chap. 8, pp 219 sq) with a quick breakdown as follows:

  1. Stage 1 overwrites motor engrams with and without external load.
  2. Stage 2 increases mechanical stability and balance demands on newly repatterned movements through off-set loading and unilateral exercises.
  3. Stage 3 builds muscle endurance through repetition of the (loaded) motor patterns trained at Stage 2.
  4. Stage 4 applies progressive overload first to the repatterned movement of Stages 2-3, then by introducing less technically demanding but more “loadable” movements (loaded squats, pulls, hinges & presses).
  5. Stage 5 is for athletes only and reintroduces the training of physical qualities needed for their sport, if different from 3-4.

In the case of the chronic sitters Stage 1 would involve : (1) waking up sleepy asses re-learning to activate the inhibited gluteal and abdominal wall complex; and: (2) re-learning to activate the t-spine erectors. Clearly, both corrections are together necessary for the “TGU-problem” to be solved. The first should be rather obvious: the TGU involves the gluteal muscle during the bridge and lunge phases (E-F and G-H transitions Fig. 3) and the abdominal wall maintains spinal stability throughout. As for (2), inhibition of the t-spine erectors results in excessive kyphosis (the “hunched-forward” posture), which in turn limits overhead reach (Fig. 5), placing additional stress on both the shoulder muscles and the lower spine during the TGU. Conversely, the process of “solving the TGU-problem” is the process of correcting both a sleepy ass an inhibited gluteal and abdominal wall complex and an excessive kyphosis.

Fig. 5 Inhibited (A) vs active (B) t-spine extensors in overhead reaching.

Insufficient overhead reach also compromises the lumbar spine during overhead extension tasks (including the F-G and G-H transitions of Fig. 3). Consider subjects A and B of Fig. 5 and picture an imaginary line going through the glenohumeral joint and the point of the skull where A’s and B’s ear would be. If B were holding a kettlebell overhead, the center of mass of that kettlebell (resting on B’s forearm) would be placed on that line. Without getting into too many details, the system constituted by B and the bell is optimally balanced, and therefore requires the least amount of energy to maintain (see SBL (III): Stability (1), “Analyzing Stability“). By contrast, A’s bell would be further forward, requiring more energy to maintain in place. This energy would be spent to maintain contraction of the shoulder girdle muscles in a biomechanically compromised position (due to the torque generated by the weight of the bell). Since (ex hypothesis) A’s t-spine erectors are inhibited, A cannot decrease the energy needed to hold the bell overhead without arching at the lower back, which requires increasing tension in the lower back erectors while decreasing tension in the anterior abdominal wall, which compromises spinal stability.

B’s posture, compared to A’s, places less stress on the spinal joints, especially lumbar (whether reaching overhead or not). Assuming that “solving the TGU-problem” amounts, for a chronic sitter, to go from A to B, it also reduces the stress on the lower back. Thus, “solving the TGU-problem” also prevents low-back pain provided that postural improvements with overhead reach carry over to postural improvements without. Since postural improvements in overhead reach are in part the result of increased tonicity of the t-spine erectors, a transfer can be guaranteed by regular practice of the TGU.


Wrapping Up: Get Stable2, Dammit!

Mechanical stability properly (stability2) is one of the least understood and most underrated physical qualities.

Mechanical stability is often confused with balance but you know better, so wouldn’t fall for the stability bullshit: no need for balance boards, BOSU® or Swiss balls [insert dirty joke about the Vatican Swiss Guard here]. A kettlebell will do. If you were not convinced of that before reading this post, I bet you are now. “But,” I can hear you say, “how is all this relevant to ‘getting started with’ kettlebells?” Well, now is the time to get to the mildly-crazy stuff I promised in the introduction.

Absent data, I cannot safely assume that couch potatoes and athletes find themselves at the extremes of the Load-Injury Curve. But I can make it a matter of definition. So, let’s define a couch potato* and an athlete* as follows:

  • a couch potato* is someone who handles loads in the low-to-moderate bracket far more often than high loads;
  • an athlete* is someone who regularly handles heavy loads in addition to loads in the low-to-moderate bracket.

Assume furthermore that the lifestyle of couch potatoes* and athletes* involves 4 hours of sitting time or more (a conservative estimate for most Europeans and North Americans) couch potatoes* and athletes* both accrue enough sitting time to affect motor patterns in such a way as to increase joint instability at low loads and disrupt movement mechanics at high loads.

Under the above assumptions, couch potatoes* and athletes* are more vulnerable to injuries than more (respectively: less) active types, including those that sit as much as they do, because couch potatoes* and athletes* have more occasions to injure themselves. Hence, they would benefit from the training regimen outlined in Steps 1 & 2. Of course, there are differences: Step 1 would be a reformed couch potato*’s daily workout but an athlete*’s out-of-bed routine. Similarly, a former couch potato* graduating to Step 2 would dial both endurance and strength training in while an athlete* would only get some active recovery.[2]

The generalization of the above to real-world couch potatoes and real-world athletes raises serious methodological difficulties. [3] There is, however, a simple way to avoid them: simply ask yourself “Am I closer to a couch potato* or am I closer to an athlete*?” and answer honestly.

If you’re close enough to one or the other, then you probably need more stability2 in your life. So get stable2, dammit!


Notes

[1] This reason is the second of three, but Tstasouline’s two other reasons, but they are irrelevant here. The first [0:18-0:21] is some Russian research that I could not track, so there’s no way to check its validity. The last one [1:45-end] because you won’t really need “high-tension techniques” for the routines in this post. In between the first and second, Tsatsouline makes some comments about Russians never using fractional plates that are either bullshit (in the technical sense) or poetic license (follow a few Russian weightlifters on Instagram and you’ll see why I think so) and a sweeping generalization about the smaller size weight plates men and women should use which is not backed by anything other than Tsatsouline’s opinion.

[2] The acceptable workload for active recovery varies according to the generalized model of training underlying one’s programming: a single-factor model only supports retaining loads, while a dual-factor may permit stimulating loads for certain types of exercises (see SBL (IV): Recovery (2) for details). In the absence of specific data about such-and-such exercise or training modality, retaining loads are the safest. To the best of my knowledge, such data is not available for the TGU. Accordingly, if you are an athlete who considers using TGU as active recovery measure, I’d recommend that: (1) you learn the TGU through a protocol similar to the in Get Up Like a Boss Turk (described in the free preview) which does not create perceivable fatigue; and (2) after the learning phase, that you determine the TGU workload that does impact your performance of choice by the procedure described in the “No Training Stimulus” section of SBL (IV): Recovery (2).

[3] Whether real-world couch potatoes and athletes are in fact more vulnerable to injuries than more (respectively: less) active types hinges on: (1) how acceptable the definitions of couch potatoes* and athletes* are for real-world couch potatoes and real-world athletes; (2) how low, moderate and high loads are identified, (i.e. as discrete loads or as total workload for a day/week/etc.); and: (3) what real-world joint injury rates would be for the populations of real-world couch potatoes and real-world athletes and low, moderate, and high loads so defined.

2 Comments Add yours

  1. Monique says:

    “Dumbbells are dumb, kettlebells are”….. kettles, or did I miss something ?

    1. More like cannonballs with handles if you ask me.

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