Muscle activation during three sets to failure at 80 vs. 30 % 1RM resistance exercise

Abstract

Muscle activation was greater at 80 % 1RM. However, differences in volume, metabolic byproduct accumulation, and muscle swelling may help explain the unexpected adaptations in hypertrophy vs. strength observed in previous studies.

Individual Responses for Muscle Activation, Repetitions, and Volume during Three Sets to Failure of High- (80% 1RM) versus Low-Load (30% 1RM) Forearm Flexion Resistance Exercise

“…Furthermore, the mean EMG amplitude responses (Figure 2) show that the fatigue-induced increases in EMG amplitude for the 30% 1RM group and no change in EMG amplitude for the 80% 1RM group resulted in similar levels of muscle activation in both groups. These results are in contrast to our recent study [12] and others [13,15,18] showing that muscle activation was higher during high-versus low-load leg extension resistance exercise to failure. The primary difference between the present study and those previous studies [12,13,15,18] is the muscle group studied.…”

“…These results are in contrast to our recent study [12] and others [13,15,18] showing that muscle activation was higher during high-versus low-load leg extension resistance exercise to failure. The primary difference between the present study and those previous studies [12,13,15,18] is the muscle group studied. Factors such as location (i.e., upper-versus lower-body), blood flow [19], architecture (i.e., pennate versus fusiform), or fiber type composition [20,21] of the muscle may influence the activation responses to high-versus low-load resistance exercise.…”

“…7-8). However, while studies have examined muscle activation [12][13][14][15] and exercise volume [12] during high-versus low-load leg extension resistance exercise, we are unaware of previous studies that have compared muscle activation or exercise volume during high-versus low-load forearm flexion (i.e., biceps curl) resistance exercise. Therefore, the purpose of this study was to compare electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high-(80% 1RM) versus low-load (30% 1RM) forearm flexion resistance exercise on a subject-by-subject basis.…”

Effects of repeated eccentric contractions with different loads on blood circulation and collagen fiber orientation in the human Achilles tendon

“…At least one week before the first exercise intervention, the unilateral one repetition maximum (1RM) of the calf muscle of each leg was measured in all subjects according to a previously described procedure 17) . In recent years, previous studies have reported that a low-load (20-50% 1RM) resistance training combined with restricted venous blood flow can result in muscle hypertrophy 18,19) .…”

Investigation of Electromyography Responses Following Resistance Exercises Done with Different Contractions

“…EMG amplitüdlerinin 1 maksimumun %80 ile yapılan dirençli egzersizlerde daha fazla olduğunu saptamışlardır. 27 Sundstrup ve ark., omuz ve boyun kaslarının EMG amplitüdünü analiz ederek tükeninceye kadar yapılan kuvvet antrenmanları sırasında bütün kaslar için doğrusal bir azalma saptamışlar ve bunu da progresif artan yorgunluğa bağlamışlardır. 28 Araş- Kroon ve ark.nın yaptıkları çalışmada, beş erkek bireye maksimum istemli kontraksiyon eşi-ğinin %40-50'si olacak şekilde sol dirsek fleksörle-rine izometrik, konsentrik ve eksentrik egzersiz verilmiş ve sonrasında ise düzenli aralıklarla kasın 30 saniye izometrik kontraksiyon testi ile y-EMG'sine ve kas performans parametrelerine bakılmıştır.…”