Analiza sprave za vježbanje nožne ekstenzije

undergraduate thesis

• Title (english): Analysis of the leg extension machine
• Author: Mario Petrac
• Mentor: Aleksandar Sušić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-02-25, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Na današnjem tržištu postoji veliki broj sprava za vježbanje koje nisu u potpunosti ergonomski
prilagođene vježbačima te predstavljaju potencijalnu opasnost za nastajanje ozljeda. Cilj ovog rada je
utvrditi prednosti, ograničenja i nedostatke sprave za vježbanje nožne ekstenzije te ponuditi rješenja
za bolju ergonomsku simbiozu vježbača i sprave. Proučavanjem nekoliko izvedbi sprave i detaljnijim
intervjuima korisnika u obližnjoj teretani, doneseni su zaključci koji omogućuju ostvarivanje željenog
cilja. Manjkavost sprave uočena je kod iskusnih i kod neiskusnih vježabača. Neiskusni vježbači
nemaju dovoljno znanja da prilagode spravu svojoj antropometriji, a oni iskusni iako imaju dovoljno
znanja, zbog ograničenosti sprave ne mogu u potpunosti postići pravilan ergonomski položaj. Na
temelju uočenih nedostataka i ograničenja potrebno je omogućiti stabilniji položaj zdjelice i donjeg
dijela leđa, spriječiti mogućnost postavljanja mehanizma poluge u nepovoljan položaj za koljeno,
omogućiti bolju podesivost, povečati krutost mehanizma valjka, poboljšati kvalitetu užeta i
rekonstruirati naslon. Stabilniji položaj zdjelice i donjeg dijela leđa postignut je stabilizacijskim
pojasom sličnim kao kod sjedišta putničkih zrakoplova. Mehanizam poluge spriječen je od
postavljanja u nepovoljan položaj za koljeno eliminacijom utora. Bolju podesivost moguće je postići
povećanjem broja utora i smanjenjem njihovog međusobnog razmaka, ili konstruiranjem specijalnih
fino podesivih rotacijskih i translacijskih mehanizama. Krutost mehanizma valjka moguće je povečati
upotrebom materijala veće fleksijske krutosti ili povečanjem poprečnog presjeka mehanizma valjka.
Upotrebom kvalitetnijeg užeta uklanja se problem labavljenja. Na poslijetku, rekonstrukcijom naslona
u obliku slova ''S'' postiže se veći potporanj kralježnici.

Abstract (english)

There are a large number of exercise machines on the market today that are not fully ergonomically
adapted to exercisers and pose a potential risk of injury. The aim of this paper is to determine the
advantages, limitations and disadvantages of the leg extension machine and to offer solutions for better
ergonomic symbiosis of the exerciser and the machine. By studying several types of the leg extension
machine and doing detailed interviews of users in a nearby gym, conclusions were made that enable
the achievement of the desired goal. Deficiency of the device was noticed in experienced and
inexperienced exercisers. Inexperienced exercisers do not have enough knowledge to adjust the device
to their anthropometry, and experienced ones, although they have enough knowledge, due to the
limitedness of the device cannot fully achieve the correct ergonomic position. Based on the observed
shortcomings and limitations, it is necessary to enable a more stable position of the pelvis and lower
back, prevent the possibility of placing the lever mechanism in an unfavorable position for the knee,
allow better adjustment, increase the rigidity of the roller mechanism, improve rope quality and
reconstruct the backrest. A more stable position of the pelvis and lower back is achieved by a
stabilization belt similar to the one that is used in the seat of passenger aircraft. The lever mechanism
is prevented from being placed in undesirable position for the knee by eliminating the groove. Better
adjustability can be achieved by increasing the number of slots and reducing their spacing, or by
constructing special finely adjustable rotary and translational mechanisms. The stiffness of the roller
mechanism can be increased by using a material of higher flexural stiffness or by increasing the cross
section of the roller mechanism. Using a better quality rope eliminates the problem of loosening.
Finally, by reconstructing the backrest in the shape of the letter "S", greater support for the spine is
achieved.

• Keywords: sprave za vježbanje; ergonomija; ozljede; nožna ekstenzija; antropometrija.
• Keywords (english): exercise machines; ergonomics; injury; leg extension machine; anthropometry.
• Language: croatian
• URN:NBN: urn:nbn:hr:235:240957
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-02-18 14:07:34