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The effects of increasing thoracic load carriage, using a backpack and body-amour ensemble, on peak aerobic power and exercise tolerance

Journal Article


Abstract


  • Introduction: Load carriage distributed around the thorax

    restricts chest-wall movement, most evidently during intense

    exercise, and this may have adverse consequences for exercise tolerance.

    In this investigation, the impact of increasing the inertial

    and elastic loading of the ventilatory pump were investigated using

    a backpack and body-armour ensemble during incremental treadmill

    exercise.

    Methods: Thirteen males (age 24.1 y [SD 4.0], mass 81.3 kg [SD

    9.2], height 1.81 m [SD 0.08]) participated in four trials (on separate

    days): unloaded control (clothing only) plus three thoracic loading

    trials using combined backpack and body-armour loads (totalmass:

    15 kg, 25 kg, 35 kg). Those masses were always configured with 75%

    of the mass carried on the back. In addition, a sub-group (N = 8)

    also completed a backpack only trial carrying 35 kg. Every trial was

    terminated at volitional exhaustion, with oxygen consumption and

    heart rate data being measured.

    Results: These loads reduced exercise tolerance in a dosedependent

    manner (control: 727 s [±27]; 15 kg: 565 [±19]; 25 kg:

    487 [±19]; 35 kg: 424 [±20]; P < 0.05). Peak heart rate was reduced

    by 2% across all loaded conditions relative to the control (control:

    195 b/min [±3]; 15 kg: 191 [±3]; 25 kg: 190 [±3]; 35 kg:

    190 [±3]; P < 0.05). Body mass-specific peak oxygen uptake was

    reduced marginally in the 25-kg and 35-kg conditions (control:

    55.59 mL/kg/min [±1.08]; 15 kg: 55.23 [±1.16]; 25 kg: 54.13

    [±1.13]; 35 kg: 53.18 [±1.29]; P < 0.05). Exhaustion occurred significantly

    earlier and was accompanied by reductions in peak tidal

    volume across all loads (control: 3.03 L [±0.09]; 15 kg: 2.75 [±0.09];

    25 kg: 2.76 [±0.08]; 35 kg: 2.74 [±0.07]; P < 0.05). Those changes

    were not compensated by increments in peak breathing frequency

    (P > 0.05). Redistributing the entire 35-kg to the backpack had no

    impact on mass-specific peak oxygen uptake, compared to 75% of

    the same load being carried on the back (backpack only: 55.83

    [±0.84] mL/kg/min versus 54.95 [±1.53]), although exercise tolerance

    was reduced (backpack only: 437 s [±22] versus 455 [±22]).

    Conclusions: The loaded backpack and body-armour ensemble

    reduced exercise tolerance in a dose-dependent manner. Notwithstanding

    the reduction in external work, peak heart rate and aerobic

    power were generally preserved, despite some impediments to the

    ventilatory pump at the point of exhaustion.

UOW Authors


  •   Peoples, Gregory
  •   Hingley, Lachlan (external author)
  •   Caldwell, Joanne N. (external author)
  •   Taylor, Nigel A.S.. (external author)

Publication Date


  • 2017

Citation


  • Peoples, G. E., Hingley, L., Caldwell, J. N. & Taylor, N. A.S.. (2017). The effects of increasing thoracic load carriage, using a backpack and body-amour ensemble, on peak aerobic power and exercise tolerance. In International Congress on Soldiers' Physical Performance, 28 Nov- 1 Dec 2017, Melbourne, Australia. Journal of Science and Medicine in Sport., 20 (Supp 2), S105-S106.

Start Page


  • S105

End Page


  • S106

Volume


  • 20

Issue


  • Supp 2

Place Of Publication


  • Australia

Abstract


  • Introduction: Load carriage distributed around the thorax

    restricts chest-wall movement, most evidently during intense

    exercise, and this may have adverse consequences for exercise tolerance.

    In this investigation, the impact of increasing the inertial

    and elastic loading of the ventilatory pump were investigated using

    a backpack and body-armour ensemble during incremental treadmill

    exercise.

    Methods: Thirteen males (age 24.1 y [SD 4.0], mass 81.3 kg [SD

    9.2], height 1.81 m [SD 0.08]) participated in four trials (on separate

    days): unloaded control (clothing only) plus three thoracic loading

    trials using combined backpack and body-armour loads (totalmass:

    15 kg, 25 kg, 35 kg). Those masses were always configured with 75%

    of the mass carried on the back. In addition, a sub-group (N = 8)

    also completed a backpack only trial carrying 35 kg. Every trial was

    terminated at volitional exhaustion, with oxygen consumption and

    heart rate data being measured.

    Results: These loads reduced exercise tolerance in a dosedependent

    manner (control: 727 s [±27]; 15 kg: 565 [±19]; 25 kg:

    487 [±19]; 35 kg: 424 [±20]; P < 0.05). Peak heart rate was reduced

    by 2% across all loaded conditions relative to the control (control:

    195 b/min [±3]; 15 kg: 191 [±3]; 25 kg: 190 [±3]; 35 kg:

    190 [±3]; P < 0.05). Body mass-specific peak oxygen uptake was

    reduced marginally in the 25-kg and 35-kg conditions (control:

    55.59 mL/kg/min [±1.08]; 15 kg: 55.23 [±1.16]; 25 kg: 54.13

    [±1.13]; 35 kg: 53.18 [±1.29]; P < 0.05). Exhaustion occurred significantly

    earlier and was accompanied by reductions in peak tidal

    volume across all loads (control: 3.03 L [±0.09]; 15 kg: 2.75 [±0.09];

    25 kg: 2.76 [±0.08]; 35 kg: 2.74 [±0.07]; P < 0.05). Those changes

    were not compensated by increments in peak breathing frequency

    (P > 0.05). Redistributing the entire 35-kg to the backpack had no

    impact on mass-specific peak oxygen uptake, compared to 75% of

    the same load being carried on the back (backpack only: 55.83

    [±0.84] mL/kg/min versus 54.95 [±1.53]), although exercise tolerance

    was reduced (backpack only: 437 s [±22] versus 455 [±22]).

    Conclusions: The loaded backpack and body-armour ensemble

    reduced exercise tolerance in a dose-dependent manner. Notwithstanding

    the reduction in external work, peak heart rate and aerobic

    power were generally preserved, despite some impediments to the

    ventilatory pump at the point of exhaustion.

UOW Authors


  •   Peoples, Gregory
  •   Hingley, Lachlan (external author)
  •   Caldwell, Joanne N. (external author)
  •   Taylor, Nigel A.S.. (external author)

Publication Date


  • 2017

Citation


  • Peoples, G. E., Hingley, L., Caldwell, J. N. & Taylor, N. A.S.. (2017). The effects of increasing thoracic load carriage, using a backpack and body-amour ensemble, on peak aerobic power and exercise tolerance. In International Congress on Soldiers' Physical Performance, 28 Nov- 1 Dec 2017, Melbourne, Australia. Journal of Science and Medicine in Sport., 20 (Supp 2), S105-S106.

Start Page


  • S105

End Page


  • S106

Volume


  • 20

Issue


  • Supp 2

Place Of Publication


  • Australia