I came across a nice randomized controlled trial focused on tendinopathy treatment from some folks in Denmark found here. The purpose of this paper was to “evaluate the effectiveness of eccentric training (ECC) and heavy slow resistance training (HSR) among patients with midportion Achilles tendinopathy.” Tendinopathy is commonly described, a bit generically, as chronic tendon inflammation. It may be more precise to say that tendinopathy could be “rather a result of a failed healing process that causes degenerative changes of the hierarchical tendon structure, neovascularization, and nerve ingrowth.”
“The associated pain is due to the neovascularization and nerve ingrowth in the tendon and is therefore a useful parameter in the diagnosis and subsequent clinical monitoring.” Consider that these criteria may or may not result in pain, but tendinopathy pain will most always come with these criteria. So, plenty of folks may have some tissue disruption, but no pain; but generally, not vice versa. Therefore, people may be training to further tolerate a physiological change, rather than ‘heal’ the tissue.
Historically, “…eccentric training (ECC) has become the principal nonsurgical choice of treatment for Achilles tendinopathy, although there is no convincing evidence that it is the most effective exercise regimen.” With specificity to eccentric loading compared to other loading strategies and tendinopathy, there is plenty of research to be done. “Nevertheless, it seems that loading itself yields positive clinical, structural, and biochemical effects with respect to tendinopathy.” This provides support that total inactivity may be detrimental to the rehabilitation process.
“It was recently shown for patellar tendinopathy that HSR performed 3 times weekly yielded superior long-term results compared with the traditional eccentric loading regimen (found here).
Subjects: “A total of 58 patients with chronic (>3 months) midportion Achilles tendinopathy were randomized to ECC or HSR for 12 weeks.”
Criteria measured: “Function and symptoms (Victorian Institute of Sports Assessment–Achilles), tendon pain during activity (visual analog scale), tendon swelling, tendon neovascularization, and treatment satisfaction were assessed at 0 and 12 weeks and at the 52- week follow-up.”
ECC Protocol: 3×15 slow 3-second eccentric unilateral on stair case knee performed with straight knees and one with bent knees, twice a day (morning and evening), 7 days a week, for 12 consecutive weeks. 2-minute rest period between sets and a 5-minute rest period between the 2 exercises
HSR Protocol: performed 3 times per week. “Each session consisted of three 2-legged exercises: heel rises with bended knee in the seated calf raise machine, heel rises with straight knee in the leg press machine, and heel rises with straight knee standing on a disc weight with the forefoot with the barbell on shoulders (Figure 1).” All movements included a bilateral full ROM and a tempo of 3 second eccentric and 3 second concentric (6 seconds/repetition), or 3/0/3.
3-4 sets in each exercise with a 2-3 minute rest between sets and a 5 minute rest period between the 3 exercises.
The repetitions and loads were as follows:
3x15RM, in week 1
3x12RM, in weeks 2-3
4x10RM, in weeks 4-5
4x8RM, in weeks 6-8
4x6RM, in weeks 9-12
The primary difference between groups was the loading time, or time-under-tension.
The thickest point of the tendon was identified and scanned via ultrasonography. The anterior-posterior distance was measured three times, then averaged for assessment. The power Doppler mode was used to assess neovascularization.
Both groups had similar improvements in pain from 0-52 weeks. “For VASH and VASR, there was a significant effect of time (VASH, P < .0001; VASR, P < .0001), but there was no significant interaction (VASH, P = .08; VASR, P = .38) or difference between groups (VASH, P = .77; VASR, P = .71)”
Both groups saw decreased tendon thickness over time. “Tendon A-P thickness decreased significantly with time (P < .0001), but there was no difference between groups or treatment interaction. Tendon color Doppler area also decreased significantly with time (P < .005), and the interaction was significant (P < .01), but there was no difference found between groups.”
Patient satisfaction was higher for the HSR at 12 and 52 weeks, compared to ECC. “The patient satisfaction with the clinical outcome at 12-week follow-up was 20 of 25 for ECC (80%) and 22 of 22 for HSR (100%; P = .052 between groups). At 52-week follow-up, 19 of 25 ECC patients (76%) and 21 of 22 HSR patients (96%) were satisfied (P = .10).”
“The main finding of the present study was that both the traditional ECC and the HSR yielded a positive clinical result in patients with Achilles tendinopathy in both the short- and long-term ranges.” So both methodologies can be effective, but is one superior?
Patient satisfaction was the only lopsided outcome (at 12 and 52 weeks), but this subjective measure could have been influenced by several factors. “A possible reason for the difference in patient satisfaction between ECC and HSR could be the time necessary to complete the 2 regimens: ECC requires two 22-minute training sessions per day, 7 days a week, for a total of 308 min/wk. The corresponding session time for HSR patients is three 36-minute training sessions per week, for a total of 107 min/wk, and this is a considerable difference in time allotment.”
Previous literature has indicated that patients may not necessarily fully recover with a “VISA-A score of 90 at a 5-year followup, with 20% of patients still having symptoms.”. There is no clear reason why some may lack of complete recovery, but it could be a result of various lifestyle factors. Another Achilles tendinopathy study showed that“…mild pain can persist up to 5 years despite the use of the ECC regimen.”
At this point I begin to wonder if a more triphasic approach should be employed, exploiting all phases of muscle contractions with various tempos. Interesting enough, “…peak forces and tendon length changes are similar during concentric and eccentric contractions. Moreover, eccentric and concentric contractions yield a similar expression of collagen, indicating that the fibroblast is similarly affected. Finally, habitual training with concentric and eccentric contractions appears to produce similar tendon growth. Thus, it is not entirely clear why avoiding the concentric component should produce a more favorable clinical outcome.” It could be that a tendon biopsy would reveal more physiological changes, possibly providing more information in future literature.
Although tendinopathy continues to leave us shrugging, I will be employing the 3/0/3 strategy when observing similar cases. At the very least, I would speculate a positive adaption to be seen from providing a phase of HSR for someone previously plateauing from an ECC protocol.
I have been discussing a paper from the University of Sydney, Australia with a few colleagues lately. The study set to explore the benefits of German Volume Training when compared to a protocol using just half the volume (10×10 vs 5×10).
“Current muscular hypertrophy and strength guidelines recommend a lower number of sets per exercise for novice/intermediate than for advanced trainers (1–3 and 3–6, respectively). Thus, these guidelines support the notion that as resistance training experience increases, muscular hypertrophy and strength gains are optimized with higher (≥3 sets per exercise) compared with lower resistance training volumes (<3 sets per exercise).” Our questions may then be: Is this a dose-response relationship? If so, is there an upper threshold where we see diminishing returns? Is there is known minimal effective dose?
As one would suspect, it is known that 2-3 sets is significantly more effective than 1 set. In fact, “…Krieger found that 2–3 sets of resistance exercises compared with a single set was associated with approximately 40% greater muscular hypertrophy and strength increases.”
“Krieger also noted that an apparent plateau in muscular hypertrophy and strength may occur around 4–6 sets per exercise. However, Marshall et al. (26) found that after a 6-week intervention of 1, 4, and 8 sets of squats at 80% of one-repetition maximum (1RM) in trained subjects, muscular strength was only significantly greater for 8 sets than for 1 set. Therefore, it appears that the upper threshold to the dose-response relationship for resistance training volume, at least for muscle strength, may extend beyond 6 sets per exercise. It should be noted, however, that a minimum intensity of ≥65% 1RM is required to optimize gains in muscular hypertrophy and strength.”
GVT originated in the 1970’s by some national weightlifting coaches as a mass building phase, using the squat and deadlift. Typically, the protocol is 10 sets of 10 repetitions (10×10) for a compound resistance exercise at an intensity of approximately 60% 1RM or 20RM, accompanied by a rest period of 60-90s. The basis revolves around accumulating metabolic stress, a known driver of hypertrophy.
Subjects: 19 healthy males ages 19-24 years of age. Must have a training history of at least 3 days/week consistently for the last year.
Training Program: The program extended 6 weeks, with the frequency of 3 days/week with at least 24 hours between sessions.
The loads for each group/exercise varied within the range of 60-80%. “On the last set of each exercise, subjects were instructed to perform as many repetitions as possible to the point of concentric failure (i.e., volitional fatigue). The training load was increased by approximately 5–10% in the next session when subjects were able to perform at least 10 repetitions with correct technique for the final set and 10 repetitions for each of the previous sets for a given exercise.” Rest periods remained between 60-90 seconds for both groups.
Body Composition was assessed via DXA scan and muscle thickness measurements were done with ultrasonography.
1RM testing was used for the following exercises: bench press (flat), lat pulldown, and leg press.
Dietary information was obtained using a 3-day food diary, analyzed via FoodWorks, before and after the experimental training period. “Throughout the study, subjects were encouraged to increase their caloric intake by 1,000–2,000 kJ above their estimated daily energy requirements.”
30 minutes after each session, a whey compound was given to each subject with 30.8 g of protein, 0.2 g of fat, and 0.9 g of carbohydrate.
Results were summarized phenomenally by YLM Sport Science
“The primary finding from this study was that despite a larger training volume, the 10-SET group did not achieve greater increases in muscular hypertrophy than the 5-SET group.”
I believe these results are based on two things- intensity and fatigue. The 5-set group achieved slightly higher intensities than the 10-set group, given half the volume and approximately half the volume-loads. The 10-set group had sessions lasting twice as long, with approximately twice the volume-load, leading to think that is not sustainable to retain relatively high volumes and intensities over the course of a training session.
From a fatigue-management standpoint, “…this practice is usually limited to periods of approximately 6 weeks to reduce the risk of over-training and musculoskeletal injuries.” I would assume that there would be even larger differences if we observed an 8-12 week experiment.
Interesting enough, legs may require a bit more volume than upper extremity musculature. “Mechanisms that may explain this phenomenon include the lower training response of the legs due to their greater everyday use and the increased hypertrophic capacity of upper body muscles due to greater androgen receptor content.”
Limitations: It would be nice to see subjective fatigue/soreness reporting throughout the study. I would assume that near week 6, the 10-set group would report a bit of diminished vigor during their training.
In summary, we know that volume is a key variable when it comes to hypertrophy. Data seems to point to the 4-6 sets/exercise range for hypertrophic results. Beyond the upper threshold could be counterproductive leading to extended phases of overreaching / over-training.
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