Water-filled training tubes increase core muscle activation and somatosensory control of balance during squat

Light weights are as effective as heavy weights for muscle activation in the Hammerobics exercise

PURPOSE

We previously reported that a Hammerobics exercise using weights can enhance trunk and lower extremity muscles, some studies suggested that training effects could also be expected without heavy weights. If the muscle activity induced by Hammerobics swinging with a 'light plastic ball' equals or surpasses that of the isometric static squat and synchronized squat with a heavy ball, this training approach could alleviate joint strain, fostering an exercise regimen universally accessible across generations, benefit for workouts sports and rehabilitation.

METHODS

Fifteen healthy men participated in this study. By using surface electromyography, muscle activities for the abductor hallucis, tibialis anterior, tibialis posterior, peroneus longus, rectus femoris, biceps femoris long head, semitendinosus, gluteus maximus, multifidus, and internal oblique muscles were measured during a light Hammerobics synchronized squat (HSS-light), Hammerobics synchronized squat, and conventional isometric squat, and statistically compared.

RESULTS

The front-to-back tibialis anterior activity of HSS-light was significantly higher than that of conventional isometric squat. The activities of all other muscles, except for the multifidus, were not significantly different between these exercises in the front-to-back and back-to-front phases. Compared to the Hammerobics synchronized squat, the light Hammerobics synchronized squat showed no differences in front-to-back tibialis anterior, rectus femoris, biceps femoris long head, and internal oblique activities and back-to-front abductor hallucis, tibialis anterior, rectus femoris, and internal oblique activities.

CONCLUSION

The HSS-light could stimulate muscles to the same level as the conventional isometric squat without weight bearing. While the HSS-light was less effective than the Hammerobics synchronized squat, there was no significant difference in internal oblique, rectus femoris, and tibialis anterior activities between these exercises. Hence, the HSS-light is an exercise method that can be viable approach to promoting accessible workouts sports and rehabilitation.

Quadriceps and gluteus medius activity during stable and unstable loading exercises in athletes. A cross-sectional study

The aim of this study was to evaluate the muscle activation of the vastus medialis, vastus lateralis, and gluteus medius during different strength and stability exercises with a water tank compared with a sandbag. A cross-sectional study was conducted in the Functional Anatomy Laboratory, and the sample consisted of 28 athletes. The main outcome measures were surface electromyography (dependent variable), water tank and sandbag, and exercise type (independent variables): Isometric Single Leg Stance (ISLS), One Leg Deadlift (OLDL), Front Rack Forward Lunge (FRFL), and Lateral Lunge (LL). Repeated measures analysis of variance (ANOVA) revealed a significant Group × Time interaction in gluteus medius root mean square (RMS) (F = 14.198, p < 0.001, ŋ2 = 0.35), vastus lateralis RMS (F = 24.374, p < 0.001, ŋ2 = 0.47), and vastus medialis RMS (F = 27.261, p < 0.001, ŋ2 = 0.50). In the between-group analysis, statistically significant differences were observed in gluteus medius RMS in the ISLS: 28.5 ± 15.8 water tank and 20.8 ± 12.6 sandbag (p < 0.001, ŋ2 = 0.08) and OLDL: 29.7 ± 13.3 water tank and 26.5 ± 13.1 sandbag (p < 0.001, ŋ2 = 0.01). In vastus lateralis in ISLS: 30.4 ± 37.6 water tank and 19.0 ± 26.7 sandbag (p < 0.001, ŋ2 = 0.03). In vastus medialis in ISLS: 14.2 ± 13.0 water tank and 7.0 ± 5.6 sandbag (p < 0.001, ŋ2 = 0.12), OLDL: 21.5 ± 16.9 water tank and 15.5 ± 10.7 sandbag (p = 0.002, ŋ2 = 0.04), and LL: 51.8 ± 29.6 water tank and 54.3 ± 29.3 sandbag (p = 0.017, ŋ2 = 0.00). These results confirm significantly greater activation of the gluteus medius and vastus medialis in the ISLS and OLDL exercises, and of the vastus lateralis in the water tank ISLS exercise. However, the vastus medialis shows greater activation in the LL exercise.

Effect of Instability Training on Compensatory Muscle Activation during Perturbation Challenge in Young Adults

Balance requires constant adjustments in muscle activation to attain force steadiness. Creating appropriate training can be challenging. The purpose of this study was to examine the effects of 2 weeks of front squat instability training using a water-filled training tube on force steadiness during an instability challenge. Control (CON, n = 13) and experimental (EXP, n = 17) subjects completed pre- and post-testing for EMG variability by completing one set of 10 repetitions with a stable and unstable training tube. Electrodes were placed bilaterally on the anterior deltoid, paraspinal, and vastus lateralis muscles. CON subjects completed 2 weeks of training using a stable training tube, while EXP subjects trained with a water-filled instability tube. EMG data were integrated for each contraction, and force steadiness was computed using the natural log of coefficient of variation. CON results showed no changes in force steadiness for any condition. EXP showed significant reductions in EMG activation variability across all muscles. These results indicate a significant training effect in reducing muscle activation variability in subjects training with a water-filled instability training device. Improvements seen in these healthy subjects support the development of training implements for a more clinical population to help improve force steadiness.

Peroneal muscle activity during stable and unstable load exercises. A cross-sectional study

OBJECTIVE

To evaluate the muscle activity of the peroneus longus during the execution of different unstable load exercises compared to stable load exercises.

DESIGN

Cross-sectional study.

SETTING

Functional Anatomy Laboratory.

PARTICIPANTS

28 healthy athletes.

MAIN OUTCOME MEASURES

Surface electromyography (sEMG), unstable load (water tank), Stable Load (Sandbag), type of exercise (Isometric single leg stance, single-leg Romanian deadlift, front rack forward lunge and lateral lunge).

RESULTS

The repeated measures ANOVA revealed significant Group ∗ Time interaction in Root Mean Square (RMS) (F = 51.307, P < 0.001, ŋ² = 0.70). In the between-group analysis there were statistically significant differences in RMS isometric single leg stance in favor to unstable load (P < 0.001, ŋ² = 0.07). In the within-group analysis of RMS statistically significant differences were found in the stable load group between isometric single leg stance and single-leg Romanian deadlift (P < 0.001, ŋ² = 0.05).

CONCLUSIONS

Single leg stance exercise with unstable load showed higher peroneus muscle activity than stable load. However, no peroneus muscle activity differences were found between unstable and stable loads for single-leg Romanian deadlift, frontal rack forward lunge and lateral lunge. Single-leg Romanian deadlift with stable load showed higher peroneus muscle activity than isometric single leg stance with stable load.

Influence of Loads and Loading Position on the Muscle Activity of the Trunk and Lower Extremity during Squat Exercise

This study aimed to investigate the effect of the load and bar position on trunk and lower extremity muscle activity during squat exercise. High bar back squats (HBBS) and low bar back squats (LBBS) were performed in random order at 50%, 60%, and 70% loads of one repetition maximum by 28 experienced healthy adult men who had been performing squats for at least one year. Before the experiment, the maximal voluntary contraction of the vastus medialis, vastus lateralis, rectus femoris, biceps femoris, rectus abdominis, transverse abdominis, external oblique, and erector spinae muscles was measured by means of surface electromyography. In addition, eccentric and concentric exercises were performed for 3 s each to measure the muscle activity. There was a significant difference in muscle activity according to the load for all muscles in the eccentric and concentric phases (p < 0.05), indicating that muscle activity increased as the load increased. In addition, in the comparison between HBBS and LBBS, significant differences were shown in all lower extremity muscles and all trunk muscles except for the external oblique in the concentric phase according to the bar position (p < 0.05). HBBS showed a higher muscle activity of the lower extremity in the eccentric and concentric phases than in LBBS, while LBBS showed a higher muscle activity of the trunk muscle in the eccentric and concentric phases than in HBBS (p < 0.05). HBBS requires more force in the lower extremity than LBBS and is particularly advantageous in strengthening the muscular strength of the quadriceps. In contrast, LBBS requires more muscle activity in the trunk than HBBS and is more effective in carrying heavier loads because of the advantage of body stability. This study suggests that rehabilitation experts apply the bar position and load as important variables affecting the intensity and method of training for target muscle strengthening of the lower extremities and trunk.

Differences in trunk and lower extremity muscle activity during squatting exercise with and without hammer swing

Perturbation exercises enhance lower limb and trunk muscles, and adding swing perturbation while loading during exercise might improve muscle activation or strength. This study aimed to check variations in trunk and lower limb muscle activity during conventional isometric squats, and whether it will change with or without swing using the Hammerobics-synchronized squat method. Twelve healthy men participated in this study. Activities for the abductor hallucis, tibialis anterior, tibialis posterior, peroneus longus, rectus femoris, biceps femoris long head, semitendinosus, gluteus maximus, multifidus, and internal oblique muscles were measured using surface electromyography during a Hammerobics-synchronized squat and conventional isometric squat. Muscle activities were statistically compared between squat methods. Hammerobics-synchronized squats significantly activated the abductor hallucis, tibialis anterior, tibialis posterior, peroneus longus, semitendinosus, and multifidus muscles, in both phases, compared with the conventional isometric squats. The Hammerobics-synchronized squat exercise can be considered for trunk and foot stability exercise.

The Effect of Aquabag Use on Muscle Activation in Functional Strength Training

Context: Although training with an aquabag (AB) has gained popularity, there is a lack of evidence of its effect. This study wanted to evaluate the effect of AB implementation on muscle activity of core and lower limb muscles during 3 functional exercises. Design: Cross-sectional observational study. Methods: Twenty healthy subjects performed a squat, lunge, and step-up, while using a stick and an AB. Surface electromyography signals were recorded from the trunk, pelvis, and thigh muscles in the dominant leg. Linear-mixed models were used to analyze the normalized surface electromyography signals. Results: Results demonstrated a significant increase in muscle activity of the back muscles during all 3 exercises (P < .001 to P = .003), abdominals during squat (P = .034) and step-up (P = .046), hamstrings during lunge (P = .008) and step-up (P = .008), and gluteal muscles during lunge (P < .001 and P = .010, respectively). Conclusions: These results indicate that an AB promotes functional strength training by demanding compensatory/additional activity of both stabilizing muscles (specifically in the core and pelvis regions) and prime movers of the lower limb. The authors recommend the use of an AB to enhance training and rehabilitation effects.

Neuromuscular shoulder activity during exercises with different combinations of stable and unstable weight mass

BACKGROUND

Recent shoulder injury prevention programs have utilized resistance exercises combined with different forms of instability, with the goal of eliciting functional adaptations and thereby reducing the risk of injury. However, it is still unknown how an unstable weight mass (UWM) affects the muscular activity of the shoulder stabilizers. Aim of the study was to assess neuromuscular activity of dynamic shoulder stabilizers under four conditions of stable and UWM during three shoulder exercises. It was hypothesized that a combined condition of weight with UWM would elicit greater activation due to the increased stabilization demand.

METHODS

Sixteen participants (7 m/9 f) were included in this cross-sectional study and prepared with an EMG-setup for the: Mm. upper/lower trapezius (U.TA/L.TA), lateral deltoid (DE), latissimus dorsi (LD), serratus anterior (SA) and pectoralis major (PE). A maximal voluntary isometric contraction test (MVIC; 5 s.) was performed on an isokinetic dynamometer. Next, internal/external rotation (In/Ex), abduction/adduction (Ab/Ad) and diagonal flexion/extension (F/E) exercises (5 reps.) were performed with four custom-made-pipes representing different exercise conditions. First, the empty-pipe (P; 0.5 kg) and then, randomly ordered, water-filled-pipe (PW; 1 kg), weight-pipe (PG; 4.5 kg) and weight + water-filled-pipe (PWG; 4.5 kg), while EMG was recorded. Raw root-mean-square values (RMS) were normalized to MVIC (%MVIC). Differences between conditions for RMS%MVIC, scapular stabilizer (SR: U.TA/L.TA; U.TA/SA) and contraction (CR: concentric/eccentric) ratios were analyzed (paired t-test; p ≤ 0.05; Bonferroni adjusted α = 0.008).

RESULTS

PWG showed significantly greater muscle activity for all exercises and all muscles except for PE compared to P and PW. Condition PG elicited muscular activity comparable to PWG (p > 0.008) with significantly lower activation of L.TA and SA in the In/Ex rotation. The SR ratio was significantly higher in PWG compared to P and PW. No significant differences were found for the CR ratio in all exercises and for all muscles.

CONCLUSION

Higher weight generated greater muscle activation whereas an UWM raised the neuromuscular activity, increasing the stabilization demands. Especially in the In/Ex rotation, an UWM increased the RMS%MVIC and SR ratio. This might improve training effects in shoulder prevention and rehabilitation programs.