Resistance Training - Lab Assignment

Josh de Rooy 17226543 Resistance Training and Physiology

Do Drop Sets Make Fatigue

Worse Versus Non-Failure

Protocol in the bench press?

Resistance Training and Physiology

By

Joshua de Rooy

Student No. 17226543

Word Count: 2529

Tables: 1

Graphs: 3

1


Do Drop Sets Make Fatigue Worse When Compared With 3 x 10

Introduction

Resistance training is a form of exercise which can lead to gains in strength and

hypertrophy. The amount of fatigue accumulated during resistance training can be

manipulated in a number of ways in order to achieve successive adaptations.

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Factors such as volume and intensity of exercise are variables in which are often

varied in order to increase the amount of acute fatigue and associated

neuromuscular responses, combined with basal hormonal levels, and stimulation of

muscle protein synthesis (MPS) following exercise. These factors are identified as

the key stimulus in the adaptations proceeding resistance training. (1, 2)

In the attempt to enhance muscular fatigue, specific resistance techniques including

drop sets, supersets, tri sets, and forced repetition training have been practiced as a

means of increasing volume with altering intensities. These techniques are

commonly seen among bodybuilders, gym trainers and the general population. The

basis of stimulating fatigue has been used to warrant prescription of varying

intensity. The belief that high volumes of exercise performed at lower intensities with

minimal rest, enables high-threshold motor unit recruitment, underpins this

prescription type with little supporting evidence. (3, 4)

A large portion of research comparing different volumes and intensities, and their

effect of fatigue tends to agree that increased fatigue and accumulation of metabolic

by products (peripheral fatigue) was a necessary method in stimulating

neuromuscular response/adaptation, and variables contributing to hypertrophy,

including stimulation of Akt-mTOR pathways (increased MPS), and increased basal

hormonal level. The premise was to achieve this by prescribing low intensities with

little to no rest period, performed til failure.(1, 4, 5, 6, 7, 8). They tend to claim that

fatiguing protocols progressively increased larger MUs, using Hennemans size

principle to support these claims. (9) Rooney conducted one of the initial pieces of

research on the effects of fatigue as a stimulus, and found that no rest between sets

combined with a high volume resulted in a significantly higher increase in strength

than resting between sets of lower volume. Findings were based on assumption that

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fatiguing protocols induced increased MU recruitment, more so than non-fatiguing

protocols, also increasing recruitment of high-threshold MUs. The assumptions made

were without having measured any mechanisms of fatigue to validate the arguments.

(4)

The idea of fatiguing resistance training has been backed up with various studies

which utilize vascular occlusion in order to enhance metabolic accumulation and

increased MU recruitment. (1, 5) Suga concluded that blood flow restriction at a low

intensity could achieve the same metabolic stress and fibre recruitment that higher

intensity training could gain. However, no EMG recordings, or such measures which

would support increased high threshold MU recruitment were utilized in the study.(5)

The other side of the research tends to agree that fatigue training protocols do not

provide a more favorable outcome in regards to strength when compared with non-

fatiguing training as long as volume is kept constant. (10, 11) It is proposed that

prescribing training to failure may increase injury risk and cause discomfort, deemed

an unnecessary approach. (11) Folland, although neuromuscular factors were not

measured, proposed an alternative theory that fatigue and metabolite accumulation

is not a necessary stimulus in order for strength gains to occur. They found similar

gains in strength between a high fatigue and low allowing longer rest periods and

decreased fatigue and comfort. The high fatigue protocol used reduced load when

failure of a given load was achieve, similar to that of a ‘drop set’. (10) Burd went on

to state that in 1 vs. 3 set until volitional exhaustion, the concern should be more

about accumulating volume, than seeking to cause failure within the muscle. They

found an increase in myofibrillar protein synthesis, through signalling the Akt-mTOR

pathways, significantly longer in 3 set vs. 1 set. (12) In addition, from an endurance

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perspective, it was found that blood lactate (BL) concentration, and overall muscular

endurance was no different between training to failure or non-failure, further

supporting the fact that training to failure may not be necessary. (13)

A method used to measure approximate neuromuscular response throughout

resistance training, within the muscle, is surface electromyography (sEMG).

Increased EMG amplitude is indicative of an increase in motor unit (MU) recruitment

and MU firing rate. Both of these factors are thought to increase as the muscle

fatigues and requires more MUs in order to produce force. (12) Acute changes in the

neuromuscular system which can enhance chronic adaptation are not firmly defined,

although many aspects have been examined which may affect amplitude of EMG

signal. (2) EMG signal can be affected by many aspects including: MU recruitment

and firing rate which can indicate output from α-motoneuron, improved

syncronization of MUs, and metabolic accumulation can also affect EMG signal by

appearing to have increased muscle activation, a limitation to sEMG use. (14, 15)

Research observing effects of failure based prescriptions including ‘drop sets’ vs.

non failure or sub maximal prescription, is lacking in areas including: samples of

trained individuals, commonly practiced failure and non failure techniques, EMG

measures within these studies, and other measures analysing the types of fatigue

which may occur. Thus, the aim of this study was to analyse and compare the acute

fatigue and neuromuscular responses between a technique, the ‘drop- set’, and a

sub-maximal lower volume protocol (3 x 10). The study compares whether fatigue

and severe discomfort are needed to stimulate neuromuscular variables within

trained individuals, and determines which protocol enhances fatigue the most. The

study observes changes in sEMG signal and which protocol elicits increased activity

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amongst variables. It is hypothesized that the drop set protocol will induce an

increased accumulation of peripheral fatigue, but no differences in central fatigue

measures when comparing drop sets vs. 3 x 10.

Participants

Project: Do drop-sets make fatigue worse?

After gaining 1RM, on separate testing days subjects performed 3 x 10 of

75% 1RM, and drop sets of 60%, 50%, 40%, and 30%.

Six Resistance trained males (mean ± SD; age- 20.83 ± 0.75 years, height –

177.67 ± 6.89 cm, weight 86.38 ± 3.41kg).

Training experience was of a minimum of 12 months, with all participants

training at least 3 times per week, incorporating bench press into

programmes.

MVC was taken prior to training, after each set of the 3 x 10 protocol, and

after failure at each weight on the drop set.

Pain scale was taken prior to MVC, after each set.

Primary dependant variable analysed: Maximal isometric force (N), median

frequency (Hz), RMS (mV), and numerical pain scale.

Results

Maximal isometric force after the 3 x 10 protocol (228.51 ± 85.48) was significantly

different than before exercise (418.51 ± 117.04N, p<0.04). Similarly, maximal

isometric force after the drop set protocol (142.1 ± 60.08N) was significantly different

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than before (418.51 ± 117.04N, p<0.04). Drop sets showed significantly more

decreased force output than 3 x 10 protocol.

Maximal sEMG amplitude was seen to increase within the 3 x 10 protocol from first

set (0.36 ± 0.26) and last set (0.39± 0.29) within pectoralis major (p = 0.13). A

decrease was seen from the first drop set (0.26±0.06) to the last drop set (0.23±0.05,

p = 0.09).

Median frequency in pectoralis major progressively decreased in 3 x 10 protocol

from first set (39.63±4.98) to third set (36.83±4.84). Drop set protocol showed an

increased between 50% 1RM (36.27±6.41), and 30% 1RM (37.22±7.04). Following

both protocols, median frequency was at a similar level.

Pain scale saw a progressive increase in both protocols, with drop sets significantly

higher following last set (9.5±1.22), compared with 3 x 10 protocol (7.25±1.54).

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1 2 3 434

35

36

37

38

39

40

3 x 10Drop Set

Median Frequency Change In Pec (Hz)

Med

ian

Freq

uenc

y (H

z)

Set number/drop number

Fig. 1. Median Frequency of pectoralis major is displayed in Hz (p = 0.83). Data is

shown as the mean value with confidence intervals. A strong relationship between

pectoralis major after the last set of each protocol has a strong relationship as shown

by the r value as MF was similar in each protocol (r = 0.8)

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1 2 3 453

54

55

56

57

58

59

60

61

62

57.957.46 57.27

61.09

56.16

57.4557.8

Median Frequency - Triceps (Hz)

3 x 10Drop Set

Med

ian

Freq

uenc

y (H

z)


Fig 2. Changes in median frequency of triceps expressed as a mean between

subjects (n = 6), were measured during each set and subsequent drop in intensity

within drop sets. Early spike was seen in drop sets, but after each protocol, median

frequency was not significantly different (p = 0.61).

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1 2 3 40

1

2

3

4

5

6

7

8

9

10

3 x 10Drop Set

VAS - Numerical Pain Scale

Pain

Sca

le


Fig. 3. Pain Scale of pectoralis major is displayed numerical values (p = 0.007). Data

is shown as the mean value with confidence intervals (r = 0.99). A strong relationship

is evident between the drop set protocol and 3 x 10 as shown by the r value.

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Repetitions Completed (Mean±S.D)

Set/weight drop 1 2 3 4

3 x 10 10±0 10±0 9±1 -

Drop Set 21.5±2.74 11.17±2.79 11.83±2.56 19.5±3.78

Fig 4. The number of repetitions completed per set and percentage 1RM of each

protocol is displayed. Data is shown as the mean value and standard deviation.

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Discussion

Key findings of this study were: A drop in maximal isometric force following both

protocols, with the 3 x 10 protocol having significantly more force production than the

drop set protocol, almost two fold more, an increase in EMG amplitude from first to

last set of 3 x 10 protocol, but a decrease in EMG amplitude was seen in the drop

set protocol, no significant difference in median frequency following each protocol

was seen, and significantly more muscular pain was observed after drop sets

compared with 3 x 10 protocol.

The results of this study suggest that training to fatigue through use of drop sets

does not necessary increase the acute fatigue stimulus, or show an increase in

muscle activation when compared with a 3 x 10 protocol of higher intensity. An

increase in median frequency indicates metabolic fatigue. Although no increases

from beginning to end of either protocol can be seen, no significant difference

between groups is evident, suggesting similar accumulation of peripheral fatigue

between drop sets and 3 x 10 protocol. An increase in muscular pain observed via

the numerical pain scale indicated increased afferent feedback, inhibiting fibre

conduction, and gives an indication of damage to the fibres. Although this may

contribute to task failure, it is not necessarily proven to increase muscular fatigue.

Significantly more pain is evident within the drop sets group, raising the question, is

the pain and discomfort necessary for subsequent adaptations to occur? (11).

Increased EMG amplitude was not evident when dropping load after failure has

occurred at a given load. Activity did however significantly increase between

beginning and end of the 3 x 10 protocol, having an end EMG signal that was

significantly higher than the drop set protocol. This suggests that at 75% of 1RM,

performed not until failure, is effective in increasing motor unit recruitment, most

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likely MUs of a higher threshold. It is likely that a given MU pool is recruited in the

drop set protocol, cycling its MUs in order to maintain contraction, without exhausting

fibres. These results show that the increased MU recruitment does not correlate

training to failure with low intensity, via the drop set technique.

Aaagard measured EMG amplitude, having participants perform 4-5 sets between 3

– 10RM intensities, and progressed amount of sets and intensity in the later weeks

of the study. They found that, based on increased neural output at the onset of

contraction, higher resistance protocols was able to elicit an increase in MU

recruitment and also MU firing rate. (17) These finding are in agreement to those in

the present study as fatigue isn’t the major factor in neural mechanims. Additonally,

Vila-cha compared EMG responses between strength and endurance training

groups. The strength group used a load at an intensity between 60 – 85% 1RM, and

concluded that higher intensities allowed an increase in MU recruitment and

discharge rate, without fatiguing stimulus. (18) This is consistent with the current

study which found that an intensity of 75% 1RM showed higher EMG amplitude 60%

1RM and below. McBride conducted research on different volumes of training and

compared EMG variables. It was found that multiple set groups using a load of

10RM elicited increased EMG activity, likely due to increased synchronisation, and

increased recruitment of type II muscle fibres, due to high intensity and not

specifically fatigue. (19) Similar results are also seen by Kamen, who analysed MU

discharge rates and found that, in initial strength gains, when the high force

contractions took place, MU discharge rate was significantly increased. They also

used a 3 x 10 protocol. (20)

In contrast, research stated that lower intensities (65%, 35%, and 25% of MVC) was

able to sustain this force output by recruiting further MUs within fatiguing contraction,

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based on misinterpretation of EMG signal. (16) The measures of M-wave signal

recorded, represent increased muscle excitability, but not necessarily increased

recruitment of MUs. Amplitude of EMG measured at 65% of MVC was higher than

the lower intensities performed to failure of 20 and 35% of MVC. These two

measures combined suggest that higher intensities were more effective in

stimulating high threshold MU recruitment. (12, 16) These conclusions conflict with

the current studies finding, that higher intensities and non-fatiguing prescription

increases neural responses. Based on findings of the current study, the hypothesis is

rejected as results show that drop sets do not make peripheral fatigue worse, or

central fatigue.

The current study is not without limitations. Sample size was relatively small (n = 6)

due to time constraints. Small sample size limits reliability as larger sample size may

prove differing results and trends, minimizing statistical power. Small sample size

increases type 2 ever as the results may be more correlated with the hypothesis, as

it has been rejected. Between group differences may have been more significant and

relatable had sample size been larger. Other muscle that were not measured,

including the anterior deltoid, may have presented differing acute neuromuscular

responses when performing the two protocols presented. It is unknown why

metabolic fatigue changed showed a decrease from first to last set with the 3 x 10

protocol, and an inconsistent pattern within the drop set protocol seeing an initial

spike, followed by a drop. The finding made regarding bench press protocols can

only be generalized to specific barbell bench press. Dumbbell bench press, machine

chest presses (weight and pin weighted), incline, and decline bench presses may

induce differing responses and results compared to those sustained in this study.

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Practical Applications

Drop sets have shown to achieve an acute fatigue stimulus, but doesn’t make

fatigue significantly worse than a 3 x 10 protocol.

Based on this study, increasing fatigue through drop sets is not effective in

maximising peripheral or central fatigue measures beyond that of a 3 x 10

protocol.

A higher resistance such as 75% of 1RM, showing enhanced MU recruitment

and firing rate, is therefore more effective in gaining the ideal neuromuscular

responses, with the absence of enhanced discomfort and pain.

Within this study, the 3 x 10 protocol is simple with no adjustment of weight

needed, allowing two minutes of rest between sets.

The preferred responses were achieved through accruing 30 repetitions at

75% 1RM, compared with 64 repetitions with the intensity being lowered 4

times for the drop set protocol.

Prescription of low volume high fatiguing protocols are likely to increase

discomfort, and enhance risk of overtraining syndrome. Therefore an ideal

prescription to elicit acute fatigue stimulus is a non-failure program consisting

of 75% 1RM of 3 sets of 10 repetitions.

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Resistance Training - Lab Assignment

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