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Hiromune Obayashi, Yukio Urabe, Yuki Yamanaka, and Ryo Okuma

Design:

Randomized controlled study.

Setting:

Laboratory.

Participants:

26 healthy swimmers randomly assigned to an exercise (n = 13; Ex) or control group (n = 13; Cont).

Intervention:

The Ex group performed respiratory-muscle exercises for 10 min thrice a week for 4 wk.

Context:

Respiratory-muscle exercises are used not only in the rehabilitation of patients with respiratory disease but also in endurance training for athletes. Respiration involves the back and abdominal muscles. These muscles are 1 of the elements responsible for posture control, which is integral to injury prevention and physical performance. However, the effects of respiratory-muscle exercise on posture remain unclear.

Objective:

To examine the potential of respiratory-muscle exercise for improving posture.

Main Outcome Measures:

Spinal curvature, pulmonary function, and trunk-muscle strength were measured for both the groups at baseline and after 4 wk. The data were compared between the Ex and Cont groups with Mann–Whitney U test and preintervention and postintervention within groups with a Wilcoxon signed rank-sum test.

Results and Conclusion:

The spinal curvature was significantly different in the Ex group, indicating a decrease in the thoracic (−13.1%, P < .01) and lumbar (−17.7%, P < .05) angles. The Ex group presented with lower thoracic (−8.6%) and lumbar (−20.9%) angles at postexercise than the Cont group (P < .05). With respect to trunk-muscle strength, only trunk-flexion strength significantly increased from pretest to posttest in the Ex group (P < .05). For pulmonary function, forced vital capacity and forced expiratory volume in 1.0 s were significantly increased after 4 wk in the Ex group (P < .05). The results suggest that respiratory-muscle exercise straightened the spine, leading to good posture control, possibly because of contraction of abdominal muscles.

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Ryo Yamanaka, Shinya Wakasawa, Koya Yamashiro, Naoki Kodama, and Daisuke Sato

Purpose: The study determined whether the increase in the cross-sectional area (CSA) of psoas major, which is known as a hip-flexion muscle, by resistance training combined with running training improves the performance of long-distance runners. Methods: Subjects were 8 well-trained male long-distance runners. The personal best time in a 5000-m race was 15:10.0 (0:20.5) (mean [SD]). Each subject performed resistance training twice per week with running training for 12 weeks. The authors used 3 resistance training regimens that would train the hip flexor muscles. Training intensity was a maximum of 10 repetitions. The training amount was 3 sets × 10 times during the first 4 weeks followed by 4 sets × 10 times during the last 8 weeks. The authors measured the CSA of psoas major using magnetic resonance imaging and the performance of long-distance runners using a constant velocity running test before (pre) and after (post) the training term. Results: The combination training significantly (P < .01, d = 0.34) increased the CSA of psoas major (pre: 16.2 [1.5] cm2, post: 16.7 [1.4] cm2) and significantly (P < .01, d = 1.41) improved the duration of the constant velocity running test (pre: 500 [108] s, post: 715 [186] s). Moreover, multiple regression analysis showed that the pre to post change in the duration of the constant velocity exercise was significantly correlated with the change in CSA of the psoas major. Conclusion: The authors suggest that resistance training of psoas major with running training is correlated with an improvement in the performance of long-distance runners.

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Ryo Yamanaka, Hayato Ohnuma, Ryosuke Ando, Fumiya Tanji, Toshiyuki Ohya, Masahiro Hagiwara, and Yasuhiro Suzuki

Purpose: Increases in maximal oxygen uptake (V˙O2max) and running economy improve performance in long-distance runners. Nevertheless, long-distance runners require sprinting ability to win, especially in the final phase of competitions. The authors determined the relationships between performance and sprinting ability, as well as other abilities in elite long-distance runners. Methods: The subjects were 12 elite long-distance runners. Mean official seasonal best times in 5000-m (5000 m-SB) and 10,000-m (10,000 m-SB) races within 1 year before or after the examination were 13:58.5 (0:18.7) and 28:37.9 (0:25.2) (mean [SD]), respectively. The authors measured 100-m and 400-m sprint times as the index of sprinting ability. They also measured V˙O2max and running economy (V˙O2 at 300 m·min−1 of running velocity). They used a single correlation analysis to assess relationships between 5000 m-SB or 10,000 m-SB and other elements. Results: There were significant correlations between 5000 m-SB was significantly correlated with 100-m sprint time (13.3 [0.7] s; r = .68, P = .014), 400-m sprint time (56.6 [2.7] s; r = .69, P = .013), and running economy (55.5 [3.9] mL·kg−1·min−1; r = .59, P = .045). There were significant correlations between 10,000 m-SB and 100-m sprint time (r = .72, P = .009) and 400-m sprint time (r = .85, P < .001). However, there was no significant correlation between 5000 m-SB or 10,000 m-SB and V˙O2max (72.0 [3.8] mL·kg−1·min−1). Conclusions: The authors' data suggest that sprinting ability is an important indicator of performance in elite long-distance runners.