Pre- versus post-exercise protein
intake has similar effects on muscular
adaptations
Dominic Bachmann
522587
PE 1.15b – Nutrition in Sports
Semester: 5
16.02.201
Table of Content
Introduction
1
Main review on the topics
Schoenfeld et al., 2017
Jay R. Hoffmann et al., 2009
Jose Antonia et al., 2017
2
2
2
3
Discussion
3
Conclusion
4
References
4
Introduction
The combination of resistance training (RT) and the protein supplementation (PS) is currently
a well debated topic. To achieve the maximum success in muscle gain one needs to
5
understand this connection. Exercising leads to a rapid change of the skeletal muscle. This
mechanism triggers acute and chronic changes in the protein biosynthesis (PBS) (Chris
McGlory, 2017). To enable the body to build up muscle tissue after a workout bout, an
appropriate amount of protein must be provided. The perfect timing of the protein
consumption for the PBS is highly debated. Different studies examined that there is an
10
anabolic window of opportunities (AWO) (Lemon PW, 2002) after a workout bout in which the
protein biosynthesis in the body is enhanced. Therefore, protein supplementation within the
AW is beneficial. Nevertheless, it is unclear to what extent this anabolic window exists or if it
even exists. This paper aims to specify the timing and need of protein supplementation around
a workout bout and tries to clarify former thoughts about the anabolic window theory.
15
1
Main review on the topics
Schoenfeld et al., 2017
The study of Schoenfeld et al. 2017 examines the impact of protein timing in a 10-week
20
intervention trial. The intervention comprises two groups who perform the same workout
routine for ten weeks. The first group (PRE-SUPP) ingests 25 grams of protein and one gram
of carbohydrates immediately prior the workout bout. The second group (POST-SUPP) ingests
25 grams of protein and one gram of carbohydrates immediately after the workout bout. Both
groups must comply with a food restriction, either three hours after the workout bout (PRE-
25
SUPP) or three hours prior to the workout bout (POST-SUPP). The results revealed that there
is no significant difference in group by time interaction in body weight, lean body mass, fat
mass, fat percentage and the 1RM (Bench and Squat).
Jay R. Hoffmann et al., 2009
30
The research team of Hoffmann, 2009, conducts a 10-week intervention study to evaluate the
impact of timing of protein supplementation. Two groups of 13 strength and power trained
athletes follow a 4-days-per-week standardized split routine training program but use
different supplementation strategies. The first group ingests 42 grams of protein isolate plus
two grams of carbohydrates immediately prior and after to the workout bout. The second
35
group takes the same dose in the morning and the evening. Additionally, they have a control
group who does not consume any supplements. The results showed no significant changes in
caloric, carbohydrate or fat intake within or between the groups. Furthermore, there was no
significant change in body composition or the strength test between the supplement groups.
2
40
Jose Antonia et al., 2017
Jose Antonia et al., 2017 examines in an 8-weeks-intervention if there is difference between
supplementing 54 grams of casein in the morning or the evening in strength-trained subjects.
Each subject follows their own workout routine and is instructed to keep a food diary via
MyFitnessPal. The results demonstrated no significant difference in body composition and
45
1RM bench within or between the groups.
Discussion
Schoenfeld et al., 2017, Hoffmann et al., 2009 and Jose Antonia et al., 2017 examine the timing
of different protein supplementation around a workout bout.
Contrary to former thoughts, none of them showed a significant difference between the used
50
timing strategies within the studies. All studies used a similar intervention structure according
to the attributes of the subjects (young, exercise experienced athletes), intervention duration
(eight to ten weeks), measured parameters (body composition and strength test), dietary
records and an ongoing counseling through scientists. However, to a certain extent, all studies
do have limitations which must be considered. Schoenfeld et al., 2017 and Jose Antonia et al.,
55
2017 did not use a control group. Therefore, it is not certain if the achieved results within the
intervention are accredited to the supplementation or the workout routine. Furthermore, the
study of Jose Antonia e al., 2017 was not able to illustrate any progress at all since baseline
values and final values are not significantly different. Jay R. Hoffmann et al., 2009 used a
control group that did not consume any supplementation during the intervention.
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Surprisingly, there was no significant difference between the supplement groups and the
control group. This could be explained by the lack of a prescribed dietary plan and a protein
restriction around the workout bout for the control group. Considering the food restriction,
only Schoenfeld et al., 2017 included the calorie restriction method to ensure that results did
3
not get distorted. The study of Jose Antonia et al., 2017 did not use a supplement restriction.
65
It is unclear whether the subject used additional supplements or not. Furthermore, his study
did not use a standardized workout routine which could explain the lack of progress within
the study. Moreover, all studies used a different kind and amount of protein (Schoenfeld et
al., 2017: whey protein, 25 grams, Hoffmann et al., 2009: protein isolate, 42 gram and Jose
Antonia et al., 2017: casein, 54 grams).
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Conclusion
Former thoughts to ingest protein immediately after a workout bout to improve skeletal
muscle adaptions because of the narrow anabolic window could not be confirmed. It is just as
sufficient to ingest protein throughout the day of training to ensure maximum skeletal muscle
75
adaptions. It appears that protein timing is not as important as once thought.
References
Brad Jon Schoenfeld, A. A. (03. 01 2017). Pre- versus post-exercise protein intake has similar
effects on muscular adaptations. Peer Journal, S.15-35
Chris McGlory, M. C. (1. 03 2017). Skeletal muscle and resistance exercise training; the role of
protein synthesis in recovery and remodeling. Journal of Applied Physiology, S. 541548.
Jay R. Hoffman, N. A. (04 2009). Effect of Protein-Supplement Timing on Strength, Power, and
Body-Composition Changes in Resistance-Trained Men. International Journal of Sport
Nutrition and Exercise Metabolism, S. 172-185.
JOSE ANTONIO, A. E. (2017). Casein Protein Supplementation in Trained Men and Women:
Morning versus Evening. International Journal of Exercise Science , S. 479-486.
Lemon PW, B. J. (2002). The role of protein and amino acid supple- ments in the athlete's diet:
does type or timing of ingestion matter? Current Sports Medicine Reports, S. 214-221.
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